Another broken CV... need some advice

[MMarcoux66]

I bought a non-working CV which someone had performed the RAM upgrade, replaced the BIOS as well as the Z80.

 

First thing I noticed is that the Z80 and the BIOS were in backwards. Luckily they had socketed the chips. They also disconnected the -5v power. I correctly reoriented the BIOS and Z80.

 

I plan to start by going over the RAM chips and test the voltages. I am seeing a lot of potential issues with solder, so I will reflow the chips and test for continuity. I am also seeing these 2 capacitors chipped. See picture.

 

So I have a couple of questions before I start.

 

1. What are the chances that the BIOS and Z80 are blown since they were installed backwards?

2. Should I replace the green capacitors or do they matter if they look like they do? If replace, what would be a good replacement part?

3. Anything else I should be aware of?

 

As always, I appreciate the help!

Edited November 12, 2020 by MMarcoux66
Fixed

[rietveld]

9 minutes ago, MMarcoux66 said:

I bought a non-working CV which someone had performed the RAM upgrade, replaced the BIOS as well as the Z80.

 

First thing I noticed is that the Z80 and the BIOS were in backwards. Luckily they had socketed the chips. They also disconnected the -5v power. I correctly reoriented the BIOS and Z80.

 

I plan to start by going over the RAM chips and test the voltages. I am seeing a lot of potential issues with solder, so I will reflow the chips and test for continuity. I am also seeing these 2 components chipped. See picture.

 

So I have a couple of questions before I start.

 

1. What are the chances that the BIOS and Z80 are blown since they were installed backwards?

2. Should I replace the green circle components or do they matter if they look like they do? If replace, what would be a good replacement part?

3. Anything else I should be aware of?

 

As always, I appreciate the help!

The 'green things' are capacitors.     

[MMarcoux66]

1 minute ago, rietveld said:

The 'green things' are capacitors.     

Thanks :). 

[rietveld]

Just now, MMarcoux66 said:

Thanks :). 

They are needed.   They are super cheap and super easy to replace.   

 

BTW the z80 should be fine. It wont work backwards but should not have been damaged 

[MMarcoux66]

1 minute ago, rietveld said:

They are needed.   They are super cheap and super easy to replace.   

 

BTW the z80 should be fine. It wont work backwards but should not have been damaged 

Great. I will see if Console5 has them.

 

I was hoping that was the case with the Z80. Hopefully the bios is okay as well. The person also gave me another complete set of RAM. So I have backups of the new chips should one of those be fried. 

 

I also assuming that the -5v does not need to be hooked to the motherboard if the RAM has been replaced.

[MMarcoux66]

Would these work for the C26 and C44 capacitors? They are labeled 104. Looking at the CV Service Manual...

C24 .1 µf ceramic disc R72284

 

https://console5.com/store/1uf-10-50v-multilayer-ceramic-capacitor-mlcc-axial-leads.html

 

or these...

 

https://www.amazon.com/mxuteuk-Multilayer-Monolithic-Capacitor-0-1uf-104/dp/B08B3VCK42/ref=sr_1_3?dchild=1&keywords=104+capacitor&qid=1605147795&sr=8-3

Edited November 12, 2020 by MMarcoux66

[ChildOfCv]

Definitely replace the broken caps.  They could easily short out.  Either link should work.

 

-5V also goes to the controllers, but there are reports that it's not strictly necessary.  But if you see weird joystick issues without -5V connected, that's probably the reason.

 

[MMarcoux66]

Just now, ChildOfCv said:

Definitely replace the broken caps.  They could easily short out.  Either link should work.

 

-5V also goes to the controllers, but there are reports that it's not strictly necessary.  But if you see weird joystick issues without -5V connected, that's probably the reason.

 

Thank you for the confirmation on the caps. I'll get them ordered.

 

I may just hook the -5v back up. I have a feeling the person removed it when they could not get it powered up as part of the troubleshooting process.

[Falonn]

Isn't disconnecting the -5V rail one of the steps in the memory mod?  Reconnecting it would join the 5V and -5V rails together, where presumably bad things would happen.

 

The note at the top of that page (beginning with "IMPORTANT!!!") says you should make sure -5V remains disconnected.

[MMarcoux66]

26 minutes ago, Falonn said:

Isn't disconnecting the -5V rail one of the steps in the memory mod?  Reconnecting it would join the 5V and -5V rails together, where presumably bad things would happen.

 

The note at the top of that page (beginning with "IMPORTANT!!!") says you should make sure -5V remains disconnected.

It says to remove the coils and install a jumper but it doesn't say to disconnect the -5v from the board. Step 2. It says to test on step 5 to make sure that the -5 and 12 are not still going to the RAM. Not seeing where it says to completely remove the -5v from the board.

[Falonn]

That's reasonable.  I've never done the mod myself and I haven't traced the -5V path through the PCB to see how equivalent the two operations are.  I just remembered seeing that warning in the instructions months ago, so I figured I would say something just in case.  Good luck!

[MMarcoux66]

25 minutes ago, Falonn said:

That's reasonable.  I've never done the mod myself and I haven't traced the -5V path through the PCB to see how equivalent the two operations are.  I just remembered seeing that warning in the instructions months ago, so I figured I would say something just in case.  Good luck!

Thanks. I'm hoping to dig in either tomorrow night or Friday. I've never done the +5v either...  lol... I've only done composite mods. The only CVs I have had +5 RAM done to were done by Ruggers. So I know that they are done right :). This CV is kind of a science experiment for me at this point since It has the mods but probably not done right. 

 

When I turn it on with or without an Atari expansion, I am getting a black screen that flashes with a static looking screen. So, that is something to start with. 

[Ikrananka]

Also, seeing as the BIOS has been replaced with a 28 pin EPROM, double check that the mods associated with this have been completed properly (see the attached document).  For example, jumpers WJ4 and WJ5 should have jumpers added to them but the photo doesn't show them as being in place, although they might have been installed under the motherboard.  Regardless, check that WJ4 and WJ5 jumpers are in place and have continuity and that two traces have been cut as per the attached document.

BIOS_replace.pdf

[MMarcoux66]

2 minutes ago, Ikrananka said:

Also, seeing as the BIOS has been replaced with a 28 pin EPROM, double check that the mods associated with this have been completed properly (see the attached document).  For example, jumpers WJ4 and WJ5 should have jumpers added to them but the photo doesn't show them as being in place, although they might have been installed under the motherboard.  Regardless, check that WJ4 and WJ5 jumpers are in place and have continuity and that two traces have been cut as per the attached document.

BIOS_replace.pdf 603.74 kB · 1 download

Thank Ikrananka, they were under the board but both are lying on other solder points...  Not sure it if is shorting or not. So I am going to move them to the top. Thanks for the doc...  will definitely go through those steps as well as the RAM steps. It also looks like the video chip and controller chips were replaced as all are socketed now.

[Bmack36]

It also looks like part of the jumper trace is missing

 

 

[MMarcoux66]

2 hours ago, Bmack36 said:

It also looks like part of the jumper trace is missing

 

 

Good catch! I traced it back to one of the pins on the Z80. So, I could just jumper it from there. 

[ChildOfCv]

5 hours ago, Bmack36 said:

It also looks like part of the jumper trace is missing

 

 

Yikes.  That one is important...

[ChildOfCv]

16 hours ago, MMarcoux66 said:

When I turn it on with or without an Atari expansion, I am getting a black screen that flashes with a static looking screen. So, that is something to start with. 

That indicates trouble with the video output, or possibly with the clock section.  When the Atari is connected, the Atari exclusively controls the video output.  If you get static from that, check the +12V and the video subsystem.  Also check the RF output plug for bad solder joint at the PCB, or just plain broken.

[MMarcoux66]

2 hours ago, ChildOfCv said:

That indicates trouble with the video output, or possibly with the clock section.  When the Atari is connected, the Atari exclusively controls the video output.  If you get static from that, check the +12V and the video subsystem.  Also check the RF output plug for bad solder joint at the PCB, or just plain broken.

Thanks for the advice! I really appreciate it! It looks like someone removed the RF part at some point. So, I will pull that off and see what is under that. Never know what I may find under there.

[+-^CrossBow^-]

Not sure if was metioned, but part of the +5 RAM upgrade is to specifically remove the inductor and cap that drive the -5 to the RAM section. So that is likely why the -5 was removed or at least on those pics it matches what I removed on my personal CV when I did the RAM upgrade on mine. Also I can tell from the label, that is the older No Delay Bios that Console5 was selling as I have one just like it. I removed it when I had issues with Risky Rick not working as the game basically wouldn't load up at all with the modified Bios installed.

 

@Ikrananka Console5 now looks to be using your modified BIOS that they sell as it is now labeled as the Fast boot BIOS and states it is to correct issues with game compatibility. I just ordered 2 of them earlier in the week to check it out.

 

*Now I see where this was discussed further up. Yeap only the coils should be removed to cut off the +12 and -5 to the RAM section, nothing else.

[MMarcoux66]

54 minutes ago, -^CrossBow^- said:

Not sure if was metioned, but part of the +5 RAM upgrade is to specifically remove the inductor and cap that drive the -5 to the RAM section. So that is likely why the -5 was removed or at least on those pics it matches what I removed on my personal CV when I did the RAM upgrade on mine. Also I can tell from the label, that is the older No Delay Bios that Console5 was selling as I have one just like it. I removed it when I had issues with Risky Rick not working as the game basically wouldn't load up at all with the modified Bios installed.

 

@Ikrananka Console5 now looks to be using your modified BIOS that they sell as it is now labeled as the Fast boot BIOS and states it is to correct issues with game compatibility. I just ordered 2 of them earlier in the week to check it out.

 

*Now I see where this was discussed further up. Yeap only the coils should be removed to cut off the +12 and -5 to the RAM section, nothing else.

Yeah, I noticed that as well. When I ordered the capacitors, I ordered the newer bios from Console5. Got to be able to play Risky Rick and Sewer Sam :).

[+-^CrossBow^-]

4 minutes ago, MMarcoux66 said:

Yeah, I noticed that as well. When I ordered the capacitors, I ordered the newer bios from Console5. Got to be able to play Risky Rick and Sewer Sam :).

Well, I honestly don't even use my cart for Risky Rick anymore. I have the modified rom and use that on my SD cart instead. But even with the actual CV bios reinstalled, Risky Rick still would require several power on/off cycles to even boot up properly after I corrected my missing ground to pin 13 on the cartridge slot.

 

Without the ground it would boot each and every time, but only in the demo mode that was coded in a separate section of the ROM. 

 

Anyway, I'm following this thread to see how it all turns out for you.

 

[MMarcoux66]

Just now, -^CrossBow^- said:

Well, I honestly don't even use my cart for Risky Rick anymore. I have the modified rom and use that on my SD cart instead. But even with the actual CV bios reinstalled, Risky Rick still would require several power on/off cycles to even boot up properly after I corrected my missing ground to pin 13 on the cartridge slot.

 

Without the ground it would boot each and every time, but only in the demo mode that was coded in a separate section of the ROM. 

 

Anyway, I'm following this thread to see how it all turns out for you.

 

I bought the ROM from the developer for Risky Rick and use on my AtariMax. 

 

Hopefully will get time this weekend to work on this CV. I am sure that the broken green capacitors are part of the issue in addition the the missing trace back to the BIOS. Great place to start. Appreciate all the advice from this group! Definitely have my work cut out for me :).

[Ikrananka]

2 hours ago, -^CrossBow^- said:

 

@Ikrananka Console5 now looks to be using your modified BIOS that they sell as it is now labeled as the Fast boot BIOS and states it is to correct issues with game compatibility. I just ordered 2 of them earlier in the week to check it out.

 

Cool - thanks for letting me know.