atari jaguar Atari Jaguar with no video signal and no audio. Is this repairable?

[iVirtualZero]

Atari Jaguar motherboard stock image. 

Hi i picked up this NTSC Jag a while back for a really good price. It was sold as parts. It arrived but had no cables or games to test it with. I then got straight to ordering and installing the parts for it. I assumed it was the typical no power fault. I ordered and replaced the Caps, Replacement custom Bios socketed, Power Button as it was missing a power button, looks like somebody worked on this before. All of that was ordered from Console5 and installed. 
 

Then i ordered and replaced the Reg1 Sound chip and the U38 Regulator Chip commonly known to fail. I then installed the 50/60hz switch mod, a very simple mod and did the diode mod to protect the console from reverse polarity, also a basic mod. I then ordered the PSU 9v 2amps, a game Iron Solder mint in box, a boxed controller, RGB cables from Retro GameCables. I was ready to test and enjoy playing on this machine. I powered it on and no video signal, no audio. Tried it directly through the tv and nothing, no signal. I tried it through the OSSC and same thing, no sync, almost as if it wasn’t even turned on even though the Led is brightly lit. I then realised this is more complicated then i thought. 
 

I tried switching to RF and it made no difference. I undid the Diode mod, it made no difference. I went over my caps i broke two traces during the recapping process but fixed it right after i originally replaced those caps. I reflowed and tested those damaged traces and checked for other damaged traces with my multimeter, and i did not find any cut traces. I checked whether the caps were in the right place and everything was installed in the right place, in the right polarity. I reflowed the cart connector, bios, Reg1 and U38 chips and it made no difference, socketed the old bios back in and nothing.
 

I cleaned the motherboard again with ipa 99% making sure i get the cart and av connector cleaned properly with my qtips and a soft pcb brush and nothing. I then tried to tap out the audio from the RF connections using my headphone jack shorted with ground and i only get a slight puffy sound. I lastly decided to put my finger on the CPU chip and that runs warm. The Graphics chip and that pretty much runs hot, is that normal? 
 

Overall i can’t figure out what’s wrong with this Jaguar and what the cause of it’s fault is. Can anyone help me figure this out? It’s sad coming across a fault like this on a rare system. I presume the Graphics chip is dead in this machine or hopefully maybe the video encoder chip, ram, missing parts maybe, not sure. I order a replacement power inductor. 120uh/mh and will see if that fixes it when it arrives.

Edited June 21, 2022 by iVirtualZero

[+Stephen]

Can't offer much advice, but I wish to god more than anything this internet myth of everything needing recapped would go away.  If there's 15 caps on that board you replaced, you just introduced 30 more points of unknown failure (every solder point) for components that were 100% guaranteed to be working fine.

 

I'm sure you know, but I'll mention it for anyone else, the Jag needs a cart inserted in order for it to power on.

[+x=usr(1536)]

6 hours ago, Stephen said:

Can't offer much advice, but I wish to god more than anything this internet myth of everything needing recapped would go away.  If there's 15 caps on that board you replaced, you just introduced 30 more points of unknown failure (every solder point) for components that were 100% guaranteed to be working fine.

Also: repair, test, verify baseline functionality, then introduce modifications.  Installing mods during the troubleshooting process on a non-working system is also introducing more points of failure, and they are likely to be ones that make tracking down the original problem at least an order of magnitude more difficult.

 

At this point, I would suggest three things:

1. Undo any and all modifications
2. Check that you're getting good power to the PCB (e.g., is the PSU working properly, how are the voltage regulators, etc.)
3. Start from power input and work your way down from there

Check for cold solder joins everywhere, too.

[iVirtualZero]

7 hours ago, Stephen said:

Can't offer much advice, but I wish to god more than anything this internet myth of everything needing recapped would go away.  If there's 15 caps on that board you replaced, you just introduced 30 more points of unknown failure (every solder point) for components that were 100% guaranteed to be working fine.

 

I'm sure you know, but I'll mention it for anyone else, the Jag needs a cart inserted in order for it to power on.

 

53 minutes ago, x=usr(1536) said:

Also: repair, test, verify baseline functionality, then introduce modifications.  Installing mods during the troubleshooting process on a non-working system is also introducing more points of failure, and they are likely to be ones that make tracking down the original problem at least an order of magnitude more difficult.

 

At this point, I would suggest three things:

1. Undo any and all modifications
2. Check that you're getting good power to the PCB (e.g., is the PSU working properly, how are the voltage regulators, etc.)
3. Start from power input and work your way down from there

Check for cold solder joins everywhere, too.

Yes i know it doesn’t power on without the cart but i have no video signal and no audio. I recapped my entire collection by this point and had no issues with those systems. I went over my cap install and they’re all in the right place and no other traces are damaged. Also tried popping the old bios back in and it made no difference. I socketed the bios, but i did not break a single trace and it went along smoothly. I can try to desolder the socket with my desoldering station, but likely will not find anything. I undid the diode mod and it made no difference. I undid the hz switch mod and it made no difference the mods for the Jag are very basic, it’s just one or two wires for these mods. I went over my Reg1 and Voltage regulator install and no problems with the solder joints found there. None of my solder joints are cold and they’re shiny. I use high quality flux and kester branded solderwire along with a Hakko soldering iron. I can try going over all of this again but i don’t think there is a fault there. This unit originally had the power button missing and a cap replaced. So i’m not sure what the previous owner did to this. Perhaps they plugged in the wrong psu into this. My psu is sold as a Jaguar PSU, so it should be compatible as my Jag’s led is brightly lit. It works with my Master System and Megadrive. Also not sure as to if the CPU chip getting warm and the GPU (DSP) chip getting hot is the norm with Jaguars. I have the power inductor on order and will try replacing that. Will look at the caps again and use the Console5 wiki to double check whether the caps are in the right place. Will also have to test the voltage like you said. 

Edited June 22, 2022 by iVirtualZero

[+Stephen Moss]

If you are getting the correct voltages out of U38 and REG1, when you say no audio or video do you mean static or just a black screen without the the tumbling letters boot screen?

 

If the latter I am looking at a Jaguar which has that problem, I traced all the power, clock and reset lines before powering up and they were fine. Visually, there were some rought looking solder joints around Jerry but I don't think they are the issue.

What I found was that it would run very small programs on the SkunkBoard either loaded as a cartridge or from RAM so fundementally it is working, but larger programs would just produce a black screen, no audio or freeze at the first screen.

I do not know if your Jaguar has the same issue, but my current thinking is that it is likely to be an issue with either memory data lines or addressing cartridge/RAM space. I am trying to write something to test that in the hope it may shed some more light on whether or not the problem is what I suspect it is and if so to hopefully help identify it more precisely - time will tell.

 

Unfortuately, no service manual for the Jaguar that we can use to help identify any issues has been found to my knowleadge, therefore appart from checking the power supply and clock are functioning it is not a simple to resolve issues that extend beyond a failure of either of those. 

[iVirtualZero]

15 hours ago, Stephen Moss said:

If you are getting the correct voltages out of U38 and REG1, when you say no audio or video do you mean static or just a black screen without the the tumbling letters boot screen?

 

If the latter I am looking at a Jaguar which has that problem, I traced all the power, clock and reset lines before powering up and they were fine. Visually, there were some rought looking solder joints around Jerry but I don't think they are the issue.

What I found was that it would run very small programs on the SkunkBoard either loaded as a cartridge or from RAM so fundementally it is working, but larger programs would just produce a black screen, no audio or freeze at the first screen.

I do not know if your Jaguar has the same issue, but my current thinking is that it is likely to be an issue with either memory data lines or addressing cartridge/RAM space. I am trying to write something to test that in the hope it may shed some more light on whether or not the problem is what I suspect it is and if so to hopefully help identify it more precisely - time will tell.

 

Unfortuately, no service manual for the Jaguar that we can use to help identify any issues has been found to my knowleadge, therefore appart from checking the power supply and clock are functioning it is not a simple to resolve issues that extend beyond a failure of either of those. 

Thanks for the wonderful reply. With the RGB cable i did not get a signal. I only have Iron Soldier which is like some 3d like mech game. I switched to RF and tried to Auto tune my tv to find the right channel and that didn’t work. I then switched back to RGB and the RGB signal on my LCD wouldn’t be detected, but the DTV would detect a signal which would give me a black screen with some static. The audio is also static through DTV. Those two chips Reg1 and U38 have been replaced. You will notice some bridges on there but many of the legs share the same traces. I would love to figure out what’s wrong with this machine. I don’t think it’s a simple cap or regulator issue. Seems like it’s more complex than that. I will replace the inductor, but that will likely not fix it. I will try to run some further tests. But don’t know what’s going on. May need someone with an Oscilloscope to test it with. 

Edited June 22, 2022 by iVirtualZero

[vintagegamecrazy]

I'm getting the same issue as mentioned above. I am repairing a Jaguar console for a store owner that I know. It initially had no power but I replaced the IC and got power restored. I also noticed heavy rust on the AV connector card edges which I cleaned up with a small brass wire brush and got them bright shiny gold again. There is heavy rust on the cartridge pin connector as well. I tried cleaning it but no luck. Is there any chance that replacing a pin connector would fix a black screen? From my experience a non working pin connector causes the red screen upon startup. Is there any other ICs that can be replaced and any further diagnosis possible without a service manual?

[iVirtualZero]

4 hours ago, vintagegamecrazy said:

I'm getting the same issue as mentioned above. I am repairing a Jaguar console for a store owner that I know. It initially had no power but I replaced the IC and got power restored. I also noticed heavy rust on the AV connector card edges which I cleaned up with a small brass wire brush and got them bright shiny gold again. There is heavy rust on the cartridge pin connector as well. I tried cleaning it but no luck. Is there any chance that replacing a pin connector would fix a black screen? From my experience a non working pin connector causes the red screen upon startup. Is there any other ICs that can be replaced and any further diagnosis possible without a service manual?

I found this post below. The fault could either be the caps, psu, cart slot. The Reg1 or U38 chips (MC34163 & 78l05) the SRam TC514800AJ80, U30, U31: HC244

, the bios, or the MC68HC000FN16 68000 chip or that may need reflowing or replacing. Or though rare the DSP Chip SC414201FT, but 1000's they still can be found. I found 1000's of new Atari branded one's, must have been leftover stock. Best thing to do is to replace Reg1, U38, recap it, try another psu, clean cart slot with ipa and contact cleaner and game, try standard av cables and if that's not enough rule out the rest or get it tested. Unfortuanetly i tried all of that with mine, so i got my new replacement 68000 and DSP chip on order.  Schematics:https://console5.com/wiki/Atari_Jaguar

  

 

Edited October 19, 2022 by iVirtualZero

[+Stephen Moss]

I don't know if this will be of any use but I was using a recently released test software on my SkunkBoard to see how that would run in the Jaguar I am looking at.

Interestingly all the video side worked, it was when I tried the audio part to generate sound that it all crashes with a single colour screen, so it may be that the problem lies with Jerry. It does have some consistency with the fault symptoms of a pure black screen and no audio as it could mean that it booting and initialising the video but could then be crashing at the point where it creates the Jaguar Roar as that is likely to be when Jerry gets involved, if the problem proves to be Jerry related.

 

There is some dull and pitted looking solder on and near to Jerry, although around that does not necessarily mean it is the cause of the a problem, I am currently at the point where I will try and clean that up when I have time to see it that makes any difference. 

[jon5121]

Where did you order the DSP and 6800 chips? I think that's what I need to do as well.

[iVirtualZero]

On 1/29/2023 at 5:20 AM, jon5121 said:

Where did you order the DSP and 6800 chips? I think that's what I need to do as well.

I ordered it from a supplier site. Just type the DSP chip into Google and many will pop up in random supplier sites. But you will have to order a minimum of 5 which can work out to be expensive. The 68000 was ordered from eBay. But replacing those in my case didn’t fix the console. Perhaps it’s the ram chips, broken trace or something else. I have to get it checked up.