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I have a strange issue on a Turbo Duo. The Cart-Part works fine. But the CD-Drive does nothing. No spinning or Laser. Even more curious - it states, the Lid is cloed (...just a moment) although the detector switch is off/top position. Any Idea where to locate the issue ?

Did u do change your caps??

Ah, yes, I forgot:

all caps changed. It´s just the Duo recognizes the RUN-Button is pressed and instead of starting the drive - nothing. Comparing to another DUO, normally about 8 Volt are passed to the Black Plug. Here it stays 4.2 Volt... but as I never gave up a Duo unit, I will try to fix it and let you know !

Talk to thesteve. This type of problem is right in his wheel house.

After some hours of investigation, I need a clue on understanding, who the detectorswitch-circuit works. Does it activate any transistor ?

Quote from: Xenogears on 10/02/2016, 11:47 AMAfter some hours of investigation, I need a clue on understanding, who the detectorswitch-circuit works. Does it activate any transistor ?

I fear only theSteve could help. Encouraged by his IC 501 Pin-Connection, I measuerd agan at this totally treatened DUO by a very untalented solder-guy. I refurbished everything, but the mentioned issue is beyond my knowledge. What I found out:

The CD-Lid-Detector-Switch goes to D102 and from there to IC 104 - PIN 8. I am certain, it´s an output, that sould pulse H/L. It hits the Diode, the closed Detector-Switch puts 5-V through and the Drive/Laser is powered. Usually.

The sick PCB in Front of me outputs only L on IC 104. Pin 8. The DUO "thinks" the Lid is closed but as no power reaches the Diode 102, the Unit is only good for HuCards.

After several hours of reviving the Unit from the Consoles Cemetary I do not want to slaughter it only to spill Parts.  :-({|=

DUO on, guys - Dan

well my IC501 pinout should help, but in your case the system is waiting to hear from IC104
IC105 is the interface between IC501 and IC104, IC105 gets its clock from IC103

Was just working on one with the same issue
Had an open via from corrosion hidden behind the card slot
Was missing a signal at ic501

So glad I found this thread. This sounds exactly like the issue I'm having (https://www.pcengine-fx.com/forums/index.php?topic=21662.msg476976#msg476976") on my PCE Duo. No laser light, and obviously the CD doesn't spin. The Hu-card slot works perfectly fine and my system has been re-capped.

Is there a known way to test IC501 without an oscilloscope?
And where would you source a new IC501 (NEC D91317GD)?

Thanks!

you wont get a new one, used from DUO, DUO-R, SCDR2
they rarely fail
what you should be looking at is the signals to it
i use a logic probe, and if anything looks funny check it at the 6280
if they dont match trace that signal (most go through a chip by the card slot)

After a lot of measuring on the still not working CD-Unit, I am not able to localize the issue.

IC 104 Logic Probes Results:

  1 - nothing
  2 - H
  3 - L
  4 - H
  5 - nothing
  6 - H
  7 - L
  8 - nothing
  9 - nothing
10 - nothing
11 - H
12 - L
13 - nothing
14 - H
15 - nothing
16 - H
17 - nothing
18 - L
19 - H
20 - L
21 - H
22 - L
23 - L
24 - L P
25 - L
26 - L
27 - L
28 - nothing
29 - nothing
30 - nothing
31 - nothing
32 - L
33 - L
34 - L
35 - L
36 - H
37 - H
38 - nothing
39 - H
40 - nothing
41 - nothing
42 - nothing
43 - nothing
44 - nothing
45 - nothing
45 - nothing
46 - nothing
47 - nothing
48 - nothing
49 - H
50 - H
51 - H
51 - H
52 - H
53 - H
54 - H
55 - H
56 - nothing
57 - H
58 - H
59 - L
60 - L
61 - L
62 - L
63 - H
64 - H

@ thesteve - do you know the Pin for /CE / OE /WE on IC 105 or something that I could proof, to get the IC alive ?

Yours

Dan

no, but check the clock on the crystal on the cxd1167
ic105 is piggybacked off it

I measured: Clock in from the Crystal on IC 103 Pin 35 / 36 and on IC 105 Pin 90.

and?
was it running?

...Here is the Result from my Peak-Tech Logic Probe, set to CMOS/PULSE  from IC 105 - D6378GF

1 - L
2 - H
3 - H
4 - H
5 - H
6 - H
7 - H
8 - H
9 - H
10 - H
11 - L
12 - nothing
13 - nothing
14 - nothing
15 - nothing
16 - nothing
17 - nothing
18 - nothing
19 - H
20 - nothing
21 - H
22 - nothing
23 - nothing
24 - nothing
25 - L
26 - L
27 - L
28 - L
29 - H
30 - L
31 - H
32 - H
33 - H
34 - H
35 - H
36 - H
37 - H
38 - H
39 - H
40 - L
41 - H
42 - H
43 - H
44 - H
45 - H
46 - H
47 - nothing
48 - H
49 - L
50 - L
51 - nothing
52 - H
53 - L
54 - H
55 - H
56 - H
57 - H
58 - nothing
59 - nothing
60 - nothing
61 - nothing
62 - nothing
63 - nothing
64 - nothing
65 - nothing
66 - H
67 - H
68 - H
69 - H
70 - H
71 - H
72 - L
73 - H
74 - L
75 - L
76 - L
77 - L
78 - L
79 - H
80 - L
81 - L
82 - L / Pulse
83 - H
84 - H
85 - H
86 - L
87 - L/Pulse
88 - H/L/Pulse
89 - L
90 - L/Pulse
91 - H
92 - H
93 - L
94 - L
95 - L
96 - L
97 - L/Pulse
98 - L
99 - L
100 - H


Still no Change - if I press RUN the System Message is "Just a moment..." instead of "Please close cover" although the Lid is open/Detector-Switch is not pressed. No need to say, the Disk Systen would not try to spin...

ok that looks good, do the same on IC501

Old Post - new Answer: SOLVED. Damn. All the measuring for not finding a tiny solder-bridge on Resistor Array (RA512)  ](*,)

After finding that out, the Lid-Detector-Switch was recognized again.

"Please close Cover"

I did not work on the PCB for a very long time - Sometimes time is the key :-)

I have sometimes the same issue, i'm going to have a look for  RA512 too. Thank you for your answer !

So glad you managed to solve it, after over a year!  And props for coming back to document the answer, very cool.

The Point is  not only to look for the Resistor Array. Please frist always check the VIA. If they have connectivity, go on, trace connectivity from Pin to Pin

Thank you for your advice Xenogear. RA512 is fine in my duo.
My problem, like yours was, is, when "run" is pressed : No "Busy" Led activity, "Just a moment" on screen, and nothing else (no led focus, no led movement on the rail). It remains as it indifinitely.
But this problem occurs randomly. Sometimes it doesn't come for many days. Sometimes, it's here for a complete day.
Do you think I have mostly to check continuity in the area of this RA512.
By the way, do you have schematics for the cd part of the nec Duo ?
Thank you a lot.

Your Problem seems to be different from mine. I´d check the Vias supplying 5V / GND to the CD Section. I have no Schematics - sorry. Your Duo is completely recapped ?

Did you ever check the large Via hole just to the right of the 2 47UF caps right by the CD loading light? That via can get filled with old cap goop. Thus needing a good cleaning and sometimes a wire bridged through the hole to repair the 5V connection.