Messages

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboDuo/PC Engine Duo: Total capacitor replacement chart]

=>>Anybody know the full trace route for the right sound channel from beginning to end?<==

What, abbreviated schematics and technical descriptions aren't enough?  We have a lot of these here, about many of these consoles.
Try a seach for "Duo" and "schematic"....I'm pretty sure that there are numerous threads here about this, and many of them lead to other threads.  There may even be one actually related to the DUO and it's audio.

Good luck.

Charlie

[Console Repair/Mod Center / Re: Repairs & Modifications - Table Of Contents]

Good idea.  I agree that the existing method is a bit cumbersome. 

Is the intent to simply combine the various threads into common product types, or create a "shortcut to repairs" for the various products.  If the latter, do you intend to make a repair manual for each of the products?  I ask because doing that means scouring the various threads for whatever tech/repair info you can find (including any sporadic info on voltages, schematics, pot settings, et) , and compiling each piece of that data into the appropriate manual.  I suspect this is rather a large task....but good luck to you either way.

If you DO create the repair manuals, I am sure many here could help by pointing you to the various threads/posts that contain many pieces of information....I'm sure you won't have to do all the searching yourself.

Charlie

[Console Repair/Mod Center / Re: About the interface unit...]

>@Charlie: Thanks for that trace!<

No problem.
If you need the schematic of that part of the circuitry, including the actual regulators and control circuits, let me know.

Charlie

[Console Repair/Mod Center / Re: Interface Unit w. CD-Rom² problem]

I am a bit confused here.  Is this the standard IFU that has a CDROM that sits on top of it, and plugs into the back of the turbo grafx?

If so, I don't understand why, when you are using a 9v adapter on a unit that needs, at an absolute minimum, 10.5V (and actually expects about 13V)...and it doesn't work properly....that you wonder why.
If this IS the IFU that I believe we are talking about, the input jack is clearly marked 11V.  I would change the adapter first, long before I even thought about adjusting  pots.

Or, is this a different unit entirely??

Thanks for any assistance.
Charlie

[Feedback / Re: Is it possible to "Sticky" a topic?]

How about "Repair Guide - Interface Unit"?  Then I'd have someplace to "stick" the schematic(s).  (Ha!  I made a funny!)

Charlie

[Console Repair/Mod Center / Re: About the interface unit...]

>general note resistors designated R and inductors designated L might act as a fuse if reason arose<

Generally yes, in this case no...both the R and the L are not discrete components, but actual wiring.  The wire gauge is way too thick to be a fuse link.  (The L's are actually ferrite beads strung on the wire).


Also, since R101, R102, R103 and R104 are actually links of wire, you can unsolder one end of each (For R101, R102 and R104, the end farthest from the connector is recommended -- it allows you to use the wire link as a convenient voltage test point.  For R103, it's the end closest to the connector) to isolate the regulator circuitries, then quickly/temporarily reconnect one at a time to determine which "path" is the bad one.  Be sure to check all four.

Charlie

Edit: Added reference to R103 and R104.

[Console Repair/Mod Center / Re: About the interface unit...]

FYI, capacitor C141 is directly across the power input.  If you apply reverse polarity, you will almost certainly blow that capacitor.  Either check it for a short, or remove it to see if it solves the problem.  Of course, replace it when done.

Ummm, you did make sure to turn the LOCK switch "on", right?


Anyway, here's the power path:
1. From the power jack on the AVPower board, negative connects through a small jumper to the black wire, which goes to P103, pin 1, then to board ground.
2. From the power jack on the AVPower board, positive connects to the red wire, which connects to P103, pin 2.
3. From P103, pin 2, it goes to C141 (47uf, 25v) and also through L101 to P102, pin 2
4. From P102, pin 2, it goes to the Power Switch.
5. Back from the Power Switch, it goes to P102, pin 1.
6. From P102, pin 1 it goes through L102 to P404, pin 2.
7. From P404, pin 2, it goes to the Lock Switch.
8. Back from the Lock Switch, it goes to P404, pin 1.
9. From P404, pin 1, to goes to D101 anode (that's the "30D2"), which is the polarity protection diode.
10. Out D101 cathode it goes to C101, C102 and C103 (330uf, 25V) in parallel, then continues on to R101, R102, R103, and R104, which are actually jumpers.  These jumpers feed the separate parts of the actual power supply circuit.  This was done so each circuit could be powered individually during board design.

You should be able to trace the power to that point.  Make sure to check the voltage against both grounds, the one on the AVPower jack, and the common ground on the board.

Charlie

PS. I suppose, if there was a place to upload it, like say a sticky entitled "Repair Guide - Interface Unit", someone might be pursuaded to supply an abbreviated schematic of the above circuit......(I'm just saying..!)

Edit: Added reference to R103, R104.

[Console Repair/Mod Center / Re: Could this be the wheels to fix cd-rom2?]

I had already looked into that.  On the original web-site (which may actually be the one you are quoting), he gives detailed instructions on how to modify those gears to work on the CD.  The effort is a bit extensive, so that may be where a lot of the cost comes from.

Basically, you buy the original gears, sand the plastic down a bit to make their surfaces rough enough so they can be glued together, glue them in a specific position, then drill out the center holes with a specific size drill bit (done either by hand or with a very small, slow drill).  Keeping the two gears co-centric requires either really good hand-eye co-ordination, or a very well machined jig.

I suppose part of the cost is also shipping, and currency conversion.

Just some FYI

Charlie

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboExpress/PC Engine GT: Video Fix]

Just out of curiosity, why have you narrowed the problem to the transformer?  What did you do to prove it is not the circuit that "runs" the transformer? 

Charlie

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboExpress/PC Engine GT: Video Fix]

It is VERY possible for the xfmr to appear bad if there is capacitor acid on the board, at or near the terminals.  The acid is conductive, the backlight power is high voltage and low current; any type of capacitor gunk in the circuit will simply short out the high voltage.  I'd make sure the entire area around the transformer and related circuitry is absolutely clean before I'd assume the xfmr is bad.

As a test, you can temporarily connect just the primary (input) side of the xfmr to the circuit, leave the secondary (output) disconnected, and then check the voltage.  That will tell you if the xfmr is good or not.

Charlie

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboExpress/PC Engine GT: Video Fix]

He is checking for AC, right?  Not DC?  And the value can be anywhere between 100V and 300V; typically 225V.

Charlie

[Console Repair/Mod Center / Re: Turbo Grafx/PC engine CD Gear replacement available! $15 shipped]

$15 is an excellent price for this.  I priced a bulk custom-made gear set for the CD drive, the best price I could get was $18 in bulk of 500 pieces.  Throw in package/shipping, and I would have charged at least $25 just to break even.  I cannot see any reason why anyone would not pay $15 and do the fix yourself.  I have done a number of gear replacements on these drives, and the effort is minimal. 

The other option was to do as Steve did,.. buy a "compilation" set of gears, find which one gear in which package of many gears would actually be usable, and proceed to buy multiples of that package.  (And gain lot's of excess gears in the process)

Good job, Steve!!

Charlie

[Console Repair/Mod Center / Re: Need some info for a replacement part]

DAN114 on the diode...It's connected to C325, a 100uf.  They are part of the "anti-thump" line that turns the sound off when you first turn on the system, so you don't get a big "WHUMP" out the speakers.  However, if you're having a problem in that area, you may very well have blown transistor 308.  That would keep the sound off permanently.  If so, it's a 2SA1073.

Charlie

[Console Repair/Mod Center / Re: My continuing CDROM2 problems]

It's been  pointed out to me that, in my original post, I listed VR104 twice.  I'll edit that post as soon as I check my notes.

Charlie

Edit: Original post edited 6/6

[Console Repair/Mod Center / Re: My continuing CDROM2 problems]

Aha!  Take a break then!

Just a quick check:
>> I'm measuring the front 2 pins<<
I assume you mean the front 2 pots, and that you of course know to measure the center pin of each pot against ground.

Good luck
Charlie

[Console Repair/Mod Center / Re: My continuing CDROM2 problems]

Hmm, not sure I understand:

1. >>got everything except the audio CD - which makes perfect sense with no IFU<<
The CD audio plays WITHOUT the IFU.  In fact, IIRC, you can't even plug the headphone in if the CD is in the IFU.  And I would have thought "Run standalone, with power supply and headphones; NOT installed in interface unit" was self-explanatory....or am I mis-interpretting your statement?

2. >>I can't measure it and play it at the same time<<
Why not?  I do!  I presume you take the bottom off, and either set the unit up on a pedestal, or hang it over the edge of a table/bench.  Either way, the power can be pluggged in, the headphone can be plugged in, the CD can be playing, and you can measure the pots while adjusting.  In fact, you can even start the CD playing, then turn the unit on it's side (with the pots on top, of course) and do the measure/adjust that way.

Charlie

[Localizations, Games, Apps, Docs / Re: Suggest retro arcade games for Arkhan (and others) to create for the PCE]

>>What? No support for Dig Dug? How about Qix, or Q-bert? Or even the original Mario Brothers (not Super at all).<<

Absolutely, positively support this with all my heart and soul.  (That means I like it)

Charlie

[Console Repair/Mod Center / Re: DUO RAM]

Cool pix!  Thanks!  Never opened the IFU (don't think I have the docs on it, just the DUO), but it make sense that the DUO and the CD/IFU would use very similar circuitry, right down to probably the same chips in most/all cases ('1167, '1082).

Charlie

[Console Repair/Mod Center / Re: My continuing CDROM2 problems]

Playing (or, at least, attempting to play!) an AUDIO cd.  Run standalone, with power supply and headphones; NOT installed in interface unit.  (Kind of hard to set it up for access to the pots in that configuration anyway.)

Since you are so mis-configured anyway, just press the PLAY button, then set the pots to the values given. Once you do that, pull the power plug, wait about 10 seconds, then start anew.

Try to get the audio cd to play track one at first.  Turn the volume up full, you'll need to listen to the audio to fine-tune the starting point.  You want no pops/crackles at full volume...they will vary as you tweak the pot, so go slowly.  (Important:  Make sure you have changed the caps first...you may mistake an audio hiccup caused by weak caps as an audio hiccup caused by mis-allignment.  There is a subtle difference in the sound).

If/when you get track one audio cleanly, I can give you some hints on full tuneup.

Charlie

[Console Repair/Mod Center / Re: DUO RAM]

Sorry, guys, but the "data flow chart" is going to have to wait.  After I dug deeper into the system, I realized that it will probably take about 4 sheets to show the entire path from the laser into memory in enough detail to be useful; not something I can do in just a few days!  It would help if you could narrow it down a bit!

As an FYI, I went back to the manf's data again, and the tech specs on the DUO (dated 1993):

1. U105 is listed as "U105 uPD6378 ASIC".  It got classified by the tech data as an ASIC ("Application Specific Integrated Circuit") because of it's "application specific" status; it would be more correctly identified as an ASSP ("Application Specific Standard Product") which is how the IC manufacture classified it.  It is, by manufacturers definition, a CR ROM Drive Controller.  It has the following characteristics:
a) Error correction function on chip
b) Error correction repeatable 3 times(real-time)
c) Double-speed replay capability
I also strongly believe it has SCSI capability.

2. U501 is listed as "U501 uPD91317 CPU".  It is a custom ASIC (as classified by the manufacturer) with the following characteristics (as per the data sheet):
a) High integration: 17k gates
b) Accepts MEGA macro and ANALOG macro blocks
c) Accepts RAM up to 64k bits
d) Survives latch-up currents over 1A
e) Power consumption: 15uw/MHz/cell
f) Ram access time 25ns for 256x8


Charlie

[Console Repair/Mod Center / Re: REPAIR GUIDE - TG16 CD/PCE CD laser swap guide (pictorial)]

Update note:
The UPD9309, which I mentioned is the SCSI Interface IC, is officially described as a "CD ROM drive controller"; the description says nothing about its interface capabilities.  (I missed that extra line of text in my notes).  However, it's probably ok to call it "CD ROM drive controller with SCSI interface", even that's not officially correct.  Or maybe just make a reference to the SCSI port in a comment.

Charlie

[Console Repair/Mod Center / Re: My continuing CDROM2 problems]

Got a VOM?
Start with these voltages:
VR101 = 2.0V
VR104 VR102 = (see below)
VR103 = 2.5V
VR104 = 2.5V
VR105 = 3.5V

For VR104VR102, set it to 2.25V, then adjust the other pots slightly to see if you can get reliable results.  If not, increase VR104VR102  to 2.30V, repeat pot adjustments.  If not, increase VR104VR102 to 2.35V, etc....upto VR104VR102  = 2.65V.

Note that all voltages above are not "set in stone", all the values will vary slightly, including VR104VR102  start voltage and end voltage.

Most important...the results of a pot change may NOT be immediate, so after each change, wait a few seconds for the circuit to settle in.


Charlie

Edit 6/6

[Console Repair/Mod Center / Re: DUO RAM]

Well, I don't want to tie up this thread with a name/type discussion; the intent is to help with the ram usage.  Just a note that I didn't say "the D91317 is an MCU", I said it is a CPU.  U104 is an MCU.

>>Have you used a logic analyzer ...<<
No, I don't have any specific reason to do so.  I don't need that depth of analysis for the typcial repairs.

I'll update the schematics with data busses in the future.

Charlie

[Console Repair/Mod Center / Re: PC engine or duo controller pin out]

For the DUO:
1 = red
2 = white
3 = black
4 = yellow
5 = blue
6 = green
7 = brown
8 = grey

Maybe they're the same for you?

Charlie

[Console Repair/Mod Center / Re: DUO RAM]

Unless the SampleClock output is being used as a interrupt on U501?  But it shouldn't be necessary unless U501 would be unable to keep up with streaming the voice data; after all, it should be able to since it's the source.  Wonder if the limitations of U502 required it to receive more attention in a more timely manner, and there needed to be some kind of feedback from it to U501 (via the SampleClock) to say "ready for next data NOW"?  However, that seems strange given that the ADPCM clock is sourced by U501 in the first place; U501 should certainly know when it's done something....so it should know when it's time for the next sample without U502 asking for it.

Incidentally, U901 (HUC 6280), U902 (HUC 6270), and U903 (HUC 6280) are all custom ASIC's; the 6280 just happens to have an actual CPU core.   It is not strictly correct to call it a CPU.  The real CPU in the DUO is 501, the 91317. Thus, the SampleClock input may actually be an interrupt function.  (Just to make matters worse, U105 is an ASIC in design, even though it actually is a microprocessor, and U104 is an actual microcontroller! --AGGHHH!!)

Hmm, if we continue to NOT have a standard naming convention here, our discussion will quickly become more of an effort to determine "which chip is he talking about", rather than actually making progress on the functionality of the system.  Thus, your statement:
>>But I wasn't expecting to see ADPCM ram going to the ASIC<<
confused me.  It doesn't go to the ASIC, it goes to the CPU (in my definitions), even though it's the same U501.  Would it be acceptable to simply use the IC designators on these chips, rather than the chip numbers or their functions?

Charlie

PS: Had a thought --  maybe I'll make up a flow chart of interconnections via buss, rather than individual pins.

[Console Repair/Mod Center / Re: DUO RAM]

>>IC510/IC509 are 4bit rams for the M5205 ADPCM playback chip (IC502), but they're accessed as a single 8bit read/write by the CPU<<
Agreed, realizing that the CPU is U501

>>both the M5205 and both ram chips tie into the ASIC<<
The ram chips tie only into the CPU.  Is that what you meant when you said ASIC? If so, then agreed.  I indicate the M5205 connections in reply #7, under "501 pin data".  

>>the ADPCM is actually generating the IRQ <<
Confused on this one.  There is no IRQ type pin/connection on U502.  There is only the VoiceDdata (4 lines), Clock in, SampleClock out, and Reset.  Not to mention that there is no need for a chip of this type to do anything with interrupts anyway.

Should I add U502 to the schematic, or is the text sufficient?

Charlie
 
PS: Did no one realize I spelled "bidirectional" incorrectly???  Edited on 6/17

[Console Repair/Mod Center / Re: DUO RAM]

Schematics updated, text edited 6/16.

Charlie

[Console Repair/Mod Center / Re: TG-CD: Total capacitor replacement chart + useful info]

C300 is in parallel with C301.  They are the input voltage filter caps. 
The fact that you run well without that cap only means that the other caps on that same circuit have picked up the slack....but also that they are working harder, which means premature failure.  Of course, you know that the caps are prone to that anyway, so no news there.  Also, when you use the CD with the TG16 interface, the caps and power supply in the interface are helping to support proper operation.

Charlie

[Console Repair/Mod Center / Re: DUO RAM]

No, haven't yet sold anything.  But I am getting ready to sell some CD systems on ebay, as soon as I get around to taking the pictures, etc.

[Console Repair/Mod Center / Re: Missing resistors]

On the DUO, the part numbers are different.  But the IC pins are obviously the same.  Here's what I have:

Pin 40, 4700 (4.7k)
Pin 33, 6200 (6.2k)
Pin 26, 8200 (8.2k)
All three of these resistors connect to a 1000 (1k) that connects to a transistor.
There is a 27000 (27k) on pin 20 that also connects to the same point on the transistor.

These values seem close to what you found.

Charlie

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboDuo/PC Engine Duo/R/RX: Laser Swap & Adjustment Guide]

I agree...this sounds like the normal "can't quite get the pots set right" problem.  This has happened to every CD drive I have repaired.  You need to move the pots in small increments (then wait a second or two) until you get the desired results, then keep going until it dies, then go back to the middle sweet spot.  

Of course, if you have a VOM, it's quite a bit easier.  I'm sure the voltages are on some thread here somewhere.

Charlie

[Console Repair/Mod Center / Re: DUO RAM]

I may have some of the actual RAM usages/names mixed up, but I am fairly sure of the interconnects.

Here's some notes that may fill in the blanks of your data:
1. 502 comms with 501, who in turn comms with 105.
Here's 502 pin data:
a) Voice data VD0-VD4 on pins 4-7 respectively
b) VCK, VRST, VXT on pins 14, 15, 16 respectively
c) ADPCM out pin 10

Here's 501 pin data:
a) Voice data VD0-VD4 (to U502 ADPCM) on pins 89-86 respectively
b) VCK, VRTS, VXT (to U502 ADPCM) on pins 82, 92, 93 respectively
c) CD data in/out on pin 86 (?)
d) CD LRCK on pin 88
e) CD CLK on  pin 90 (?)

2. Using the 23C4001 data for 515 is close enough -- you can use the pin data of 515 in my diagram to pick up the minor pin differences.

3. 105 is shown in part in my diagram, you have the address buss and data bus, and some supporting lines.  What you need, I think, is the interconnect between 105 and 501.  I can give you this additional 105 data:
a) RST on pins 49 & 99 (tied together) connect to U104 pin 22 (Reset)
b) pins 3-10 are connected to U104 pins 56-49 (port D) respectively (8 lines)
c) pins 17-12 are connected to U104 pins 41-46  (port F) respectively (6 lines)
d) pins 94-96 are connected to U104 pins 59-61 (port A) respectively (3 lines)
e) pins 38, 39, 41-46 are connected to 501 pins 103-96 respectively (8 lines)
f) pins 56, 32, 33, 35 (tied to 54), 55 and 57 are connected to 501 pins 119, 118, 115, 117, 116, 114 respectively (6 lines)
g) pins 18-20 are ALE, WR*, RD* to U104  pins 40-38 (ALE, WR*, RD*)respectively
h) pin 93 drives transistor 105, which connects to 104 pin 14 (port C)

I do not think it is a coincidence that items B and E, and items C and F, have the same number of lines.  It is likely that the same data is being transferred between those three IC's.
Note that U104 data is available on the 'net.

I will clean up my diagrams in the near future, after we agree on the final data.

Charlie

Edit 6/16
Edit 6/17

[Console Repair/Mod Center / Re: DUO RAM]

Here is U106 interaction with U105



Good luck

Charlie

Edit 6/16

[Console Repair/Mod Center / Re: DUO RAM]

Since U106 is a standard SRAM, I can certainly get the address and data buss info between it and U105, as well as CE*, WR*, etc.  I believe the data comes into U105 on pin 86?

However, U105 does a lot more than talk to U106, it's the main ASIC supporting U501, the '91317 CPU.  Hope the address/data info will be sufficient.

Charlie

[Console Repair/Mod Center / DUO RAM]

As per a members request, here is some data on the DUO RAM system:



(Note U515 pin 24 --- still working on it)

Charlie

Edit 6/16
Edit 6/17

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboDuo: Sound Fix]

NPN it is, the damn "arrow" on the emitter is so small, I can't really see it; probably should have looked up the part number to verify.

Charlie

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboDuo: Sound Fix]

Aha! Found it.  Its a 2SC2412 PNP used as a diode regulator at 8.2VDC.  It provides 8VDC VCC for quite a number of IC's in the audio section.  This same 8 volts also provides a 4VDC source for other uses.

And, now that I think of it, I am pretty sure I mentioned this transistor before in some post of my own quite a while back! (Charlie slaps forehead with palm - DOH!).  Must be getting old;  I'll  look it up later.

Anyway, thanks!

Charlie

[Console Repair/Mod Center / Re: Making an RGB amp]

If you want to make a test board that way, it will probably be good enough to let you determine if it is worth making the production board.  (You will find out real fast how critical component layout is when you are working with video signals!)  

If you use SMT components, the tallest parts will be the tantalums; with them on both sides, you're total board thickness will approach .250".  Will a 1"x1"x.25" pcb fit into your available space?  You can get shorter caps, but they qualify as a "speciality" item, and can cost up to $1.00 more each.  

Without knowing the actual space you have available (or it's specific shape), I guess you won't know unit you try it.

Hint: cut a few pieces of standard corregated cardboard box (usually .05" to .10" thick) to the proper shape to drop into your console in the selected area, then stack them up until something hits.  That will give you a close approximation to the allowable PCB length, width and height

Charlie

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboDuo: Sound Fix]

An "out-of-scope" question about the DUO was raised in the "REPAIR GUIDE - TG16 CD/PCE CD laser swap guide " thread, so I put the answer here, and added a reference note there
---------------------------------------
Couldn't find a "Q304", but I did find a "U304"; it's the POR (Power-On Reset) chip, not a regulator.  However, it is connected directly to U302, which IS a regulator.  It provides power for the ADPCM (U502), the DAC (U201), and the anti-thump, mute, and de-emphesis circuits.  I expect that it is the routing of the tracks that caused the bad connection to be physically at the pin on the U304, but electrically U304 is not involved with actually supplying power to anything.

Good catch!
Charlie

[Console Repair/Mod Center / Re: REPAIR GUIDE - TG16 CD/PCE CD laser swap guide (pictorial)]

I put the Q304 stuff in the "REPAIR GUIDE - TurboDuo: Sound Fix" thread..it's more appropriate there.

Charlie

[PCE/TG-16|CD/SGX Discussion / Re: Wow...]

Hmm,
I'm not sure if you are applauding to the example statements, or to the "go-away" statement!

Charlie

[PCE/TG-16|CD/SGX Discussion / Re: Wow...]

Ok, you guys obviously don't get it.  So, let me give you an example:

"85% NEW" is just like your girlfriend being 85% pregnant!

Or, on a more personal level, it's like you yourself being 85% dead!

See, simple.

(OK, I'll go away now)

Charlie

[Console Repair/Mod Center / Re: REPAIR GUIDE - TG16 CD/PCE CD laser swap guide (pictorial)]

FYI:
1. Got TWO CD Rom's repaired, with parts on order for the second two.  Yay.  EBay here I come!
2. Haven't forgotten the Q304 thingy, just been sick recently.  Data coming soon.

Thanks
Charlie

[Console Repair/Mod Center / Re: Making an RGB amp]

There are a number of RGB amp threads here, some for op-amps and some for transistors.  In them, the various pros and cons are discussed, including the op-amp type and impedance issues.  (I'm too lazy to find them now, but they ARE here).  I remember specifically that I was the one who guessed what op-amp was actually being used before that info was even published.

$25 is not too much to spend for a pre-fabricated PCB, especially if you consider that the PCB kit is probably a high-volume (= low cost per board) item; the Expansion Interface board I show here, given that it is low-volume (can't get much lower than one!), cost about $150, plus my time in design and component install.  But given, as I said, that both the op-amp circuit and the transistor circuit are available here, just use one of the prototype houses that will make the PCB for $9.99, buy the parts, and build it!

So, anyone want to do some research and determine what size PCB you actually could install in whatever unit, preferably in all three dimensions?  Then let's see what circuitry will fit on it. (Hmm, don't forget you need cable connectors some place!)

Charlie

[Console Repair/Mod Center / Re: Making an RGB amp]

Don't know about a CORE unit, but if you simply want a really small RGB unit, there is a schematic someplace here of a simple unit showing 4 transistors.  If you use SMT components and tantalum caps, it should easily fit on a one inch square board.  Since I don't know the abilities of each and every TG unit (I only have a TG-16 and a DUO), I'd first check to see if that same transistor-based circuit actually works on the target unit before making the final PCB.  Next question is, how much room do you actually have in the target unit?  As I said, I am not familiar with the various units, but I'd think that each one should certainly fit a PCB that small --- wouldn't it?

Maybe a better approach would be, tell me how much room you actually have for a PCB (in three dimensions if possible), and I'll see what kind of board will do the job?  Or maybe a picture of the inside of a unit, and we'll see what kind of irregular shaped PCB will fit.  Of course, there is still the matter of installing the connectors, unless you'll accept a cable through a hole someplace.

Charlie

[Console Repair/Mod Center / Re: Making an RGB amp]

Sorry, still not sure what your goal is.

If you want to make the "worlds smallest(?) RGB amp" only , it would fit onto a PCB about 1" square, but you might need to put parts on both sides.
--OR--
if you want to make the "worlds smallest(?) video amp" only, well... it would fit onto a PCB about 1" square, but you might need to put parts on both sides.
--OR--
etc, etc.

Point is, obviously if you remove those functions you don't want, you get smaller!  But my specific goal is the EPROM emulation, so I need socket space...which lends itself nicely to the daughterboard concept I mentioned previously.  And in that case, it makes no sense to design for a fixture to go INSIDE the console (DUH).  But that makes me ask....if RGB is your target, aren't there a number of RGB amps already around here?  And aren't they pretty small already?

Or do you have some other intent?

Charlie

[Console Repair/Mod Center / Re: REPAIR GUIDE - TG16 CD/PCE CD laser swap guide (pictorial)]

Ok, let me check my notes.  Based on what you say, Q304 may be in the power supply.  I'll dig into my data and post some info.

Charlie

[Console Repair/Mod Center / Re: Making an RGB amp]

You should be able to estimate the size based on the DIN connector, which obviously fits into the back of the TG.

I ran this sucker on my late-model Sony monitor (on the VGA port).  The result went something like this:
(exagerated to make a point):
Monitor: "I see you have properly formatted Horizontal Sync at 15 KHz"
Charlie "YAY!"
Monitor: "I see you have properly formatted Vertical Sync at 60Hz"
Charlie: "YAY!"
Monitor: "Unfortunately, I can't run that slowly!"
Charlie: "AGGH!"

The RGB and/or Composite video work great (and the audio is a given).  I can run 3 TV's at the same time, if I also use the RF output of the TG itself.

Not too sure it would be cost effective to sell, though.

Don't understand the "how do you make it" question...you lay out a PCB based on the schematic, have it made, buy the parts, and populate it; just like any PCB.   Or did I mis-understand the intent of your question?

Charlie

[Console Repair/Mod Center / Re: Making an RGB amp]

If you're speaking of the RGB booster, it obviously has the R and G and B output already, so you'd probably just want the video. (unless you want the H & V sync's so you can use the VGA connection?).

The audio amps are just buffers, I wanted to protect the TG console.

Prom socket is for, ...well....proms (DUH!).  Actually, if you look closely you can see the four holes in the center; these are to mount the daughter board which is intended to be a EPROM simulator for fast program development (connects to PC for download).  The pins on the daughter board plug directly into the socket.

Charlie

[Console Repair/Mod Center / Re: REPAIR GUIDE - TG16 CD/PCE CD laser swap guide (pictorial)]

>> Have you heard of ...<<
I don't think so, but I don't know what specific fix you mean. 

There is a lot of DUO audio repair info here, particularly the block diagrams (= abbreviated schematics), that should allow anyone with reasonable soldering ability to fix DUO's.  Is there something new?

Charlie