Video signal/graphics issue with TG16

[tailspin]

Greetings, I'm a new poster.  I last used my TG-16/Booster some 15 years ago and decided to get it out of storage as my son is now old enough to play some games with dad.  I hooked it up to my Aquos LCD and while the hucards worked, some graphics are not being displayed (background is missing in games like AirZonk, Dragon's Curse, in Bomberman93 we see the Bombermans but not the walls or bombs.  I tried both the RF connection and the RCA connection from the TurboBooster but I get the same result.  Thinking that modern LCDs may not support the video signal out of the TG16, I then hooked it up to a 10 year old 27" tube TV from but I was dissapointed to see the same result.  I now think there may be an issue the TG16 itself and I was hoping some of you may know the problem and possibly how to resolve it.

[grahf]

First of all, welcome! There are a lot of long-time TG/PCE owners on here. It sounds like it could be as simple as a dirty hucard slot, since it's been sitting for so long. Try inserting/removing the card about 20 times, and see if that changes anything. If not, there are a lot of folks on here you can help you with getting the thing repaired if need be.

[Keith Courage]

Try putting a little bit of rubbing alcohol on the hu card pins and move it in and out of the system a few times to see if it cleans it out. I've never seen a system not display parts of a game before unless the game itself was bad. If any game you put in is doing this then it could be dirty inside.

[thesteve]

i have a copy of DE that does that

[tailspin]

Aha! The TG16 unit was dusty when removed from storage and while I wiped the outside it is likely that the contacts inside are still dirty.  The hucards were in their sleeves so they should be fine.  I will try the rubbing alcohol trick with Keith Courage so that I won't care if it damages the card. This sounds much simpler than "replacing  the crystal".

[PunkCryborg]

Also clean the contacts of the hu card really well with an eraser. I have had some games that were glitchy and appeared clean but doing this fixed the problem.

[esteban]

Welcome, tailspin. Hopefully your next update will bring good news  .

[NecroPhile]

Welcome aboard, tailspin (not to be confused with that crappler known as talespin).  Best of luck with your TG.

[tailspin]

Unfortunately, after several attempts to clean the contacts by pouring rubbing alcohol on a HuCard and repeatedly re-inserting, it did not resolve the problem with the graphics.  I'm not that familiar with the architecture of the TG16 but my understanding is that there are two 8bit graphics chips?  Since it is always the backround that is missing, could it be that one of the chips or board is defective so that only the output of one of the chips is working?  It would make sense that game design would have one chip dedicated to rendering the objects and the other the background.

At this point I'm wondering if it may be cheaper to buy a used working console.  Any ideas?

[nat]

I'm not that familiar with the architecture of the TG16 but my understanding is that there are two 8bit graphics chips?

You've been listening to too much SEGA propaganda! Contrary to what you've been led to believe, there are actually two 16-bit graphics chips: Hu6260 and Hu6270A. One is called the VDC, the other the VCE.  Neither one controls "just" the backgrounds, or the other "just" the sprites. They work in tandem.

Since it is always the backround that is missing, could it be that one of the chips or board is defective so that only the output of one of the chips is working?  It would make sense that game design would have one chip dedicated to rendering the objects and the other the background.

I totally see where you're coming from but unfortunately, that's not the case. At least not with the two GPU chips. It's possible some of the VRAM is bad, however. Someone who has dug a little deeper into these things can probably clarify. It's not unheard of for RAM to go bad, in fact, there was someone here a number of years back that was having graphical glitch issues and it turned out one of the VRAM chips was hosed.

[thesteve]

or a few GT's that had trace damage to the V-Ram cause graphic issues

[Freezer]

Hello, I'm pretty new to this board, but I'm glad I found it because of the wealth of knowledge here.  I don't have much experience with TG16 systems, but I have modded several Sega Genesis systems, as well as an NES and two PlayStations.  If I were in your shoes here's what I would try.

The TG16 motherboard has 5 or 6 surface mount ICs on it.  I would use a fine tip soldering iron to carefully touch and reflow the solder on each pin of all the surface mount ICs.  It would seem to me that it's possible there are one or more cracked solder joints that could be causing this.

Of course, what I'm recommending may be beyond what you're able or comfortable to do.  First it requires a special bit to open the system up.  You'll also need a good solding iron and wick to be able to remove the RF shield.  And you need a small tip for your soldering iron so you can reflow each pin without bridging to the next.  But assuming you have all this, you might give it a try.

Again, I'm by no means an expert when it comes to repairing these systems, this is just what I'd try if I were in your shoes.  Good luck!

[tailspin]

Thank for the suggestions.  The cost and trouble of acquiring the specialty bit, tip and VRAM chip without knowing if it will resolve the problem is a lot less appealing to me than forking out $35 for a used working console.

[NecroPhile]

Thank for the suggestions.  The cost and trouble of acquiring the specialty bit, tip and VRAM chip without knowing if it will resolve the problem is a lot less appealing to me than forking out $35 for a used working console.

That's probably what I'd do too, but don't trash this one.  I'd donate it to thesteve for possible repair or at least for parts to save other Turbobs.

[thesteve]

definatly dont toss it as its either repairable or parts.
the solder retouch sugestion is generally good practice, but these systems havent had solder issues so not a likely fix.

[tailspin]

No worries, I'll keep it for parts or a possible educational project with my son.  Assuming it is the VRAM, do some of you know what brand/spec to get and where we can buy them?

[bust3dstr8]

There are two 32K x 8 120ns and one 8K x 8 100ns SRAM both are 28-SOIC package.
They are pretty cheap and you can get them at any parts place, Mouser, Digikey, etc.

Someone might know which chip location handles each different function...I coulnd't seem to find it anywhere.