cps2 Qsound ram error

PCB problems and fixes
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kobayuz777
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cps2 Qsound ram error

Post by kobayuz777 » March 23rd, 2019, 8:13 am

I want people with knowledge to tell me. :awe:

The other day I bought a junk board.
There was no case, it was a set of A + B, but it was the one to see for the first time about a pin.

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A board ... Female
B board ... male

This has never been seen on the green board.
Is it an early type or another revision? :eh:


Since 3 to 10 ROMs are not regular ROMs, I just inserted them because they had regular ROMs.
Once you start with the suicide tester,
The tester got up. However, Q sound ram error is out.

Do you know which part of the board is broken?
Is it a RAM chip somewhere on board B or is it due to board A? :awe:

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leonardoliveira
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Re: cps2 Qsound ram error

Post by leonardoliveira » March 25th, 2019, 5:02 pm

This is what the things on your picture are.
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kobayuz777
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Re: cps2 Qsound ram error

Post by kobayuz777 » March 26th, 2019, 6:42 am

leonardoliveira wrote:
March 25th, 2019, 5:02 MP
This is what the things on your picture are.


Mr.leonardo
Thank you always for the correct advice!
Let's check the pointed out part. :awe:

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Re: cps2 Qsound ram error

Post by kobayuz777 » August 2nd, 2019, 4:01 am

I was busy with work and didn't have time to check the board. :awe:

Since I wanted to repair, I started again recently.
I will write down here in hopes that the information on CPS2 will be abundant.

As general-purpose IC was sold to shop, we purchased.
I removed it with a heat gun and replaced it with a new part.
But error does not change ... :problem:

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We also replaced BGS-A3, BGS-A4 and Z80. (The socket was attached for easy replacement in the future)
But there are still errors ...

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I examined the foot of the IC with the logic probe.
Then, it turned out that there is a difference between the normal board and this faulty board.
Is this the cause of the failure?

https://www.flickr.com/photos/183039890 ... ed-public/

I can not understand why the pins 5, 6, 7 and 13 of BGS-A3 and BGS-A4 are disconnected.
Regarding Z80, For pin 6
In the faulty board, only 0 is lit
(In the normal Z80, 0 and 1 are lit at the same time.)

Pin 6 of Z80 is marked as "CLK" when looking at the data sheet.
Does this mean that something upstream is broken? :wtf:


Image

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leonardoliveira
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Re: cps2 Qsound ram error

Post by leonardoliveira » August 3rd, 2019, 2:28 am

Try replacing Z80 RAM (28 pin SMD IC at position 2K) standard 6264 SRAM IC. The clock for the Philips DAC IC comes from the QSOUND DSP, not related to Z80 clock.
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Re: cps2 Qsound ram error

Post by kobayuz777 » August 3rd, 2019, 8:23 am

leonardoliveira wrote:
August 3rd, 2019, 2:28 am
Try replacing Z80 RAM (28 pin SMD IC at position 2K) standard 6264 SRAM IC. The clock for the Philips DAC IC comes from the QSOUND DSP, not related to Z80 clock.
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I forgot to say
I tried replacing the Z80 RAM first. I thought it was the closest to the cause because it is a RAM error. :awe:
But the suicide tester 'Qsound error' was displayed again.

I did not test with the logic probe, so I will test it later.

Is the problem of PIN6 of Z80 CPU OK?
BGS-A3 and BGS-A4 are also worried that pins 5, 6, 7 and 13 are not normal. :)

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Re: cps2 Qsound ram error

Post by leonardoliveira » August 4th, 2019, 12:01 am

Can you try BGSA3 and BGSA4 PALs on other CPS2 board? Early ones have socket, is easy to test.
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Re: cps2 Qsound ram error

Post by kobayuz777 » August 7th, 2019, 5:57 pm

leonardoliveira wrote:
August 4th, 2019, 12:01 am
Can you try BGSA3 and BGSA4 PALs on other CPS2 board? Early ones have socket, is easy to test.

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I tried replacing the PAL of a normal A board (with socket). :awe:

There was a new discovery.
Even when I attached the Faulty board BGSA4 to a Not broken A board, I got an error.
There seems to be no doubt that BGSA4 is out of order.

However, even if Not broken BGSA4 was attached to the Faulty board, the error did not disappear.

There seems to be another problem yet. ;)

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By the way, although SRAM was examined with a logic probe, there seems to be no abnormality. :)

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Re: cps2 Qsound ram error

Post by leonardoliveira » August 11th, 2019, 12:43 am

Probably your fault will be the PAL plus one of the TTL logic chips around it.

Purchase a GAL16V8 IC and program it with the correct file from this site:
https://www.jammarcade.net/wiki/index.p ... APCOM_CPS2
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Re: cps2 Qsound ram error

Post by kobayuz777 » August 15th, 2019, 6:39 am

leonardoliveira wrote:
August 11th, 2019, 12:43 am
Probably your fault will be the PAL plus one of the TTL logic chips around it.

Purchase a GAL16V8 IC and program it with the correct file from this site:
https://www.jammarcade.net/wiki/index.p ... APCOM_CPS2

https://page.auctions.yahoo.co.jp/jp/auction/f361705728

thank you for the advice! :D
I bought this.
I will exchange it when it arrives.

What causes the Z80 clock to turn off?
(Is it caused by crystal oscillator?)

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Re: cps2 Qsound ram error

Post by leonardoliveira » August 19th, 2019, 6:06 pm

Z80 clock comes from the 8Mhz oscillator box near it. So, likely oscillator box could be faulty. Z80 being dead (no clock) could cause QSOUND error. Z80 being missing or stalled could also cause blank screen if game tries to access QSOUND memory area and 68000 does not receive DTACK signal from read circuit. That causes 68000 to stall (full freeze).
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Re: cps2 Qsound ram error

Post by kobayuz777 » August 28th, 2019, 4:08 am

leonardoliveira wrote:
August 19th, 2019, 6:06 MP
Z80 clock comes from the 8Mhz oscillator box near it. So, likely oscillator box could be faulty. Z80 being dead (no clock) could cause QSOUND error. Z80 being missing or stalled could also cause blank screen if game tries to access QSOUND memory area and 68000 does not receive DTACK signal from read circuit. That causes 68000 to stall (full freeze).

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As GAL16V8 arrived, I started it normally when I connected it by writing with a ROM writer. :awe:

However, there seems to be no Z80 clock yet.
I bought a new crystal oscillator and exchanged it.
The clock remained at 0. :-o

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I think that the parts enclosed in red may be defective, so I will try to replace them.
I don't know what this is.

Chip inductor (ferrite beads)?
Is there an effect to reduce noise? :D

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Re: cps2 Qsound ram error

Post by leonardoliveira » August 30th, 2019, 4:07 am

Something shorting clock line? Have you test it to gnd and +5v for short circuit?
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Re: cps2 Qsound ram error

Post by WallGarants » October 9th, 2019, 2:29 am

O Leonard só você pra dar uma luz, estou a dias tentado resolver este mesmo problema aqui, fiz a substituição do DL 1425 pensando que era ele mais continua acusando o erro do Qsound ram, vou tentar essas alternativas que você deu.Obrigado
Atualizando o post efetuei a troca do 6264 SRAM IC e a placa subiu o som. Obrigado mais uma vez
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Re: cps2 Qsound ram error

Post by kobayuz777 » October 12th, 2019, 5:26 pm

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The reply was delayed. I'm sorry.
It was not corrected even if FB28 and FB29 were replaced.
I checked PIN11 (5V) PIN (GND) of Z80 with a tester, but it was 4.81V.
It is the same value as the A board that moves normally.
Is there a cause for DL 1425?

Where can I find the clock line? :D

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