PC Engine PI-TG001 issues

[ScoreAddict]

So I got me a PC Engine from Japan. Not working, "you can't play game". OK.



It arrived in this condition ("you can't clean console?") and with lots of issues. Would not start, only a black screen would show with a hucard inserted.



Three cold solder points around the power input! You could almost pull it out with your fingers. Now fixed.



Gameport, same story, lots of cold solder points. Fixed.



I even replaced the worn out gameport.

Alas, still only a black screen and no picture or sound. The card adapter has been thoroughly cleaned!





Next I replaced the voltage regulator and removed all of the capacitors.






New capacitators were soldered in.

Still - only a black screen.

Any idea what's wrong here and how the fix it?

A colleague of mine suspects the contacts in the card adapter are the problem and that I should switch pin 1 to "high" (with a hucard inserted).

old.pinouts.ru/Game/CartridgePcEngine_pinout.shtml

Alas, I have no idea how to do that and he hasn't told me yet. Anyone here knows what to do?

Thank you!

[Ergot_Cholera]

When you say black screen do you mean that the console doesn't power on? If it is working in any way then I think you should get something on screen, even if it is just a blank white screen.
Have you tested continuity across the fuse (obvious )?

[ScoreAddict]

The console does power on and the fuse is intact. And I'm only getting a black screen.

[NecroPhile]

You using RF?  If so, try composite off the exp bus.

[Fidde_se]

Bad connection to hucard = white screen (sometimes if you flip the power on and off rapidly it shows green or purple, or some other weird color), same if you have no card in it.

Most other faults also shows white screen...

Black.... and no sound... hmm, could be everything from small nearly undetectable cracks in the board, even under one of the three main circuits to it's not getting power at all, getting 5v out of the 7805? around 4.995 not 4v or 6v.

Worn out cables between slot and mainboard gives white screen also.

[ScoreAddict]

You using RF?  If so, try composite off the exp bus.

I've tried both RF and and expansion bus (via adapter). Same effect! There is definitely a signal from the console, but it's only a black screen.

Bad connection to hucard = white screen (sometimes if you flip the power on and off rapidly it shows green or purple, or some other weird color), same if you have no card in it.

I know. I also expected dirty contacts, but I've cleaned the card adapter very thoroughly (and several times by now).

Most other faults also shows white screen...

Exactly.

Black.... and no sound... hmm, could be everything from small nearly undetectable cracks in the board, even under one of the three main circuits to it's not getting power at all

How about the thing with setting pin 1 to "high"? My colleague was talking about soldering a cable to make this connection. Alas, he didn't say WHERE to solder it to!

getting 5v out of the 7805? around 4.995 not 4v or 6v.

I've put a brand new 7805 into this console.

Worn out cables between slot and mainboard gives white screen also.

I've also checked the connections between the slot and mainboard.

[wilykat]

So there could be issues with chips or RAMs.
DId you check very carefully for bad trace when you replaced caps? Recheck just to be sure, and check that all via's are connecting both sides.  Also maybe flex the PCB just a bit to see if there's any sign of crack or loose chip pin?

[ToyMachine78]

Could be anything. The board looks pretty corroded. Looks like it was stored in a damp location or something.

[ScoreAddict]

So there could be issues with chips or RAMs.

Worst case scenario.

DId you check very carefully for bad trace when you replaced caps?

Yes, I did. Nothing obvious.

Recheck just to be sure, and check that all via's are connecting both sides.  Also maybe flex the PCB just a bit to see if there's any sign of crack or loose chip pin?

OK.

The board looks pretty corroded. Looks like it was stored in a damp location or something.

Actually, no. The contacts look pretty normal (no corrosion/oxidation around soldering points etc.) and the capacitators may have been old but they were not bad. The board is rather dirty though. But since this console wasn't treated very nicely, no wonder.

[ScoreAddict]

ADDENDUM:

I rechecked with ANOTHER monitor (this time Commodore 1084S)! There is actually a WHITE screen when the console is switched on! (Looks like the old RGB-monitor I used before has some issues with higher contrast output.)

[Keith Courage]

to use the RF your TV needs to be set to 95 or 96 for it to work.

A white screen is no good. Could be that your ribbon cables have fallen apart at the ends so check that first.  or you have a bad Hu6280 chip.

[ScoreAddict]

to use the RF your TV needs to be set to 95 or 96 for it to work.

I know. At this point I'm only using the AV-Out-Adapter.

white screen is no good. Could be that your ribbon cables have fallen apart at the ends so check that first.  or you have a bad Hu6280 chip.

I've checked the cables.

Anyone got an idea in regards to "set pin 1 to high"?

[OldMan]

Anyone got an idea in regards to "set pin 1 to high"?

What would be the point of this? Pin 1 is Cart detect...and I don't -think- the pce actually uses that. In any case, setting it to 1 (ie, putting + voltage on it) would indicate no card connected, I think.

If you think its a problem with the cart slot, check for +5V on pin 38. That will tell you if the card is getting power.

...and you are not doing something silly, like using a US card in a JP machine and/or have a region mod set to the wrong region, are you?

[ScoreAddict]

What would be the point of this? Pin 1 is Cart detect...and I don't -think- the pce actually uses that.

The guy who recommended this to me knows what he's doing. Unfortunately, he's not the most reliable of people due to having no time, most of the time.

In any case, setting it to 1 (ie, putting + voltage on it) would indicate no card connected, I think.

You think? So you're not sure?

If you think its a problem with the cart slot, check for +5V on pin 38. That will tell you if the card is getting power.

+5V from ANY source?

...and you are not doing something silly, like using a US card in a JP machine and/or have a region mod set to the wrong region, are you?

Hey, I may be old too, but I'm not silly! ;)

[ToyMachine78]

So there could be issues with chips or RAMs.

Worst case scenario.

DId you check very carefully for bad trace when you replaced caps?

Yes, I did. Nothing obvious.

Recheck just to be sure, and check that all via's are connecting both sides.  Also maybe flex the PCB just a bit to see if there's any sign of crack or loose chip pin?

The board looks pretty corroded. Looks like it was stored in a damp location or something.

Actually, no. The contacts look pretty normal (no corrosion/oxidation around soldering points etc.) and the capacitators may have been old but they were not bad. The board is rather dirty though. But since this console wasn't treated very nicely, no wonder.

Oh. Must be the pictures. It looks like there is oxidation on several components, and it looks like some of the legs are rusted on a couple of the chips in pic 11/11.

[Fidde_se]

That could just be rosin flux, most in there is lead/tin plated copper meaning it will be green when corroded.

Sometimes when things hit the floor, like when stepping on the cable, there are extreme flex on the board leaving bigger circuits (SMD/SMT) to get loose in their pins (legs), it might look good to the untrained eye but it's not really soldered, going over everything with a microscope might be needed or even resoldering everything just to be sure.

[ScoreAddict]

Any more ideas?

[thesteve]

condition looks about average
got a logic probe? (or scope)
you need to run across the slot pins without the card and see what its doing
almost every pin should read high/low or pulse

[ScoreAddict]

I did some voltage measuring on the card slot!

pin voltage
01 0.0 v
02 2.5 v
03 1.7 v
04 0.0 v
05 0.9 v
06 3.4 v
07 1.9 v
08 3.4 v
09 3.0 v
10 2.4 v
11 4.1 v
12 2.9 v
13 2.9 v
14 2.1 v
15 4.9 v
16 5.0 v
17 5.0 v
18 0.0 v
19 5.0 v
20 5.0 v
21 5.0 v
22 5.0 v
23 5.0 v
24 5.0 v
25 2.5 v
26 3.6 v
27 2.5 v
28 2.2 v
29 2.2 v
30 0.0 v
31 0.0 v
32 0.0 v
33 5.0 v
34 5.0 v
35 5.0 v
36 5.0 v
37 5.0 v
38 5.0 v

No idea if this helps.

[OldMan]

No idea if this helps.

Some. At least we know the cart is getting power (pin 38 == 5V), and that /CART is right (0V).
The fluctuations on the address lines probably mean they are changing (if you used a meter, those are average voltages)

It's the block of 5V in the middle that bothers me; Pins 15-23 (excluding pin 18, which is GND == 0V)
should be changing as well. Yet it appears they are stuck at 5V, which is a 1.

Looks like a dead card to me. Or possibly the data lines are shorted together somewhere...

[ScoreAddict]

At least we know the cart is getting power (pin 38 == 5V), and that /CART is right (0V).

Good. At least something.

The fluctuations on the address lines probably mean they are changing (if you used a meter, those are average voltages)

I used a meter.

It's the block of 5V in the middle that bothers me; Pins 15-23 (excluding pin 18, which is GND == 0V) should be changing as well. Yet it appears they are stuck at 5V, which is a 1.

OK. Should I do some more measuring? Any suggestions?

Looks like a dead card to me. Or possibly the data lines are shorted together somewhere...

Since I have two more PC Engine consoles to test (and play) it, I can confirm that the card is in fine working condition.

So maybe it's one of the connection between the main pcb and the card slot?

[thesteve]

i thought that was without card
pins4 and 30-32 concern me

[OldMan]

pins4 and 30-32 concern me

That's A16, A13, A14, and A17, right? During boot up it reads page 0, so I could see those being 0V.
Not sure why A15 (pin 5) would be fluctuating though, so it could be an address line problem.

i thought that was without card

Wouldn't you see 0's without the card?
Either way, they should be fluctuating as the cpu acceses the card, if the addresses are changing. (As they appear to be).

My next step would be to check for a shorts between the pins, both with and without a card inserted (but with the machine off).  I know the card slot can get worn, and the connector fingers either don't make contact, or short 2 connections together. After 20+ years, it can get touchy about how the card sits.
Might be as simple as inserting the card to one side or the other of the connector.

If all seems good, its time to get a logic probe, I think.

..................................................................................................
Just to satisfy my curiosity, (and the original reason I replied at all), did your friend really
tell you to 'put a 1' on pin 1? You can tap 5V from the 7805 for that...but I don't recommend it.
Pin 1 (/CD) connects to ground inside the card; without a current-limiting resistor you'll probably blow either the 7805 or something in the card.

I'm not an expert but even I know you don't short power directly to a ground without -bad things- happening..

[thesteve]

the data lines have pull up resistors and remain high without a card

[ScoreAddict]

You know, ORIGINALLY I was told "to put 5V to pin 1". Which - naturally - blew the fuse. Hey, I'm not the one called "Japanese console expert".

Then my "buddy" corrected himself by saying he meant "pin 1 to high".

He suspected the card slot or the cable connections to be the issue. Which are certainly prime candidates on such a used up console. Not sure about a burned out IC though.

[thesteve]

the ribbon cables break on those easily so that is likely
also common are trace and via corrosion (not always visible)
3rd option is chip failure (it happens)

[ScoreAddict]

OK.

Next steps would be to unsolder the card slot-pcb from the main pcb - maybe even the card slot itself? And then use a new set of cables to connect the two pcbs together to see if that was the issue.

Too bad NEC did not go for an integrated solution in this case. Or at least use a decent way to connect the two pcbs together.

[mickcris]

You could ohm out the cable before committing to all that work as that is only one possibility.  I would check it first to make sure if it was me.

[ScoreAddict]

I've "beeped" through all the cable connections already once. But if there's a broken cable, it will not necessarily be detected this way.

[mickcris]

I've "beeped" through all the cable connections already once. But if there's a broken cable, it will not necessarily be detected this way.

Why are you thinking a wire would be broken  if your meter says it isnt?

[ScoreAddict]

I had a similar issue and in that case bending the flatband cable in one direction would make a proper contact!

So it measured correctly when I tested it, but if you bent it (accidently) in the other direction it would not. And it's even worse with these more wire like flatband cables!

[mickcris]

I had a similar issue and in that case bending the flatband cable in one direction would make a proper contact!

So it measured correctly when I tested it, but if you bent it (accidently) in the other direction it would not. And it's even worse with these more wire like flatband cables!

I see.  Still doubt that's the issue if it ohmed out ok though.  Won't hurt to replace it but it's quite a bit of work.

[ScoreAddict]

As long as it's only work I don't really mind.

Replacing one of the proprietary ICs is much more of a problem. Especially getting it in the first place!

[thesteve]

if the meter said you good, move on to checking those pins to the 6280
bad traces are about as common

[ScoreAddict]

OK. Will check those next.

[ScoreAddict]

Checkups complete!

- connections between card slot and pcb
- connections between pcb and ics 101-103
- resoldered ics 101-103

Same result. My guess: one of the ics is a goner!



You can actually HEAR the console initialising if you turn the volume up during start! But after a moment it will obviously stop. So either something from the hucard's side is "missing" - or something from the console side not responding.

[thesteve]

black screen no sound?
if you have rock-on try it as it doesnt need pixel clock for sound
im guessing the ram chip on the card slot board is bad

[ScoreAddict]

black screen no sound?

No, sorry, it's a white screen!

[thesteve]

white screen could still be almost anything