Dead Jaguars, Troubleshooting tips would be appreciated

[crash]

Hi,

I have two Jaguars that I took out of storage where they have been for the past few years, but I can't get either of them to power on. I've never had problems with them before. I have three original power supplies and they all test good. I tried cleaning the cartridge ports and the cartridges. I inspected the boards and didn't see any bulging or leaking capacitors. Are there points on the motherboard where I can put a meter or common points of failure that are known?

 

Thanks for your consideration

[JagChris]

Nm

Edited January 6, 2023 by JagChris

[crash]

Hi there,

Thanks, I remembered that a cart needs to be inserted  I was able to further clean a cartridge the power connectors and got one of the units working. I'm not sure why the other cartridge didn't work since it is new and was wrapped in plastic. In any case, the second unit red LED lights up, but it doesn't seem to output any video or sound. Any suggestions would be greatly appreciated.

[+Stephen Moss]

Did you try searching this forum and the hardware forum before posting as the solution and a method of finding it may already be present, but if it is not booting, no Jaguar roar or tumbling letters that will be very difficult to solve. If it is the same issue as a Jaguar I have, I have only been able to narrow it down to something related with Jerry as video is fine, it just appears to crash when it comes to playing audio, but I could only discover that using a SkunkBoard.

 

First double check the power, with the the power switch in its on position (try both if not sure)...

Main Power:

First measure the input voltage across C34, it is a medium size 330uF cap probably close to the power regulator (front right corner of the PCB where it angels in). If that is not easy to access then try between pin 4/5 and 7 (or 9/10/11) of the power regulator U38 (MC34163). Should read approximately 9V DC

Then try the output voltage of the regulator across C150, a large 2200uF cap also locate near to the main regulator. Should read approximately 5V DC.

 

   

[crash]

Hi, I did try searching but found one thread where the conclusion was that the owner's Jaguar was dead, and another where you recommended checking the regulators but that thread did not say where those were located. It is not booting, no sound or picture, just the red LED.

 

Thanks for the points to check, I will test.

 

Cheers

[Zerosquare]

Also, try bridging the power switch like this:

http://www.mirari.fr/g8w6

 

Sometimes this component fails.

[crash]

On 1/5/2023 at 10:41 PM, Stephen Moss said:

Main Power:

First measure the input voltage across C34, it is a medium size 330uF cap probably close to the power regulator (front right corner of the PCB where it angels in). If that is not easy to access then try between pin 4/5 and 7 (or 9/10/11) of the power regulator U38 (MC34163). Should read approximately 9V DC

Then try the output voltage of the regulator across C150, a large 2200uF cap also locate near to the main regulator. Should read approximately 5V DC.

 

   

I get ~10.71v out of R169, ~10.72v out of C34v, and ~4.9v out of C150. C150 may have some signs of leakage. Still no activity from the Jaguar.

Thanks

[Zerosquare]

Does the power LED turn on?

[crash]

Indeed it does,  just no sound or picture.

 

Thanks 

[+Stephen Moss]

Well from those voltages it sounds like the main power is up.

I cannot see why an issue with the voltage for the audio outputs would affect the system like that but you can try measuring the output voltage of REG 1 (LM78L05ACM), located about 2 inched behind the left edge of the left controller port just to be certain. Pin8 should read approximately 9V, pin 1 should read approximately 5V, al other pins are tied to GND.

 

Reset Circuit:

Try & Locate U9/TP13/T16, after power on pin 12 of U9 (TP16) should go Low (be approximately 0V) and Pin 10 of U9 (TP13) should go high (approximately 5V). That goes not necessarily mean those signals are getting to Tom & Jerry but if they are it is worth checking they are correct.

 

System Clock:

All try to locate pin 11 of U11/TP25, that is the primary system clock. The voltage you will get if it is running is unpredictable as it depends on your meter, but anything other than GND or approximately 5V would suggest it it running.

 

Very Basic tests: 

After that there is very little practical help that can be provided, as without a proper service manual which we do not have, and without an oscilloscope and ideally a logic analyser, which most people don't have access to you are essentially limited to the following...

1) The finger test, if anything gets hot very quickly that could indicate a potential fault, although better to use freezer spray if you can get it.

2) Get a good magnifier and perform a thorough visual inspection, look for bulging capacitors, signing of burning, holes in IC enclosures, dull pitted solder joints that need re-flowing, IC pins that do not appear to be soldered to the PCB.

3) If you can get hold of a SkunkBoard or something similar that essentially bypasses the Jaguars BIOS/Fastboots the Jaguar to avoid any issue that may lie there and load it with some test software like this that can be used to generate video and audio separately, that could help identify if the issue may lie with Tom, Jerry or both/elsewhere. That is how I was able to determine that the Jaguar I have that just produces a black screen, no audio/video from the Jaguar boot screen is likely related to Jerry.

 

From my own experience it is not easy tracing signals to Tom & Jerry, particularly Jerry as the pin count is rather odd and not continuous when working around it from pin 1 as the package has more pins (not connected to anything) than accounted for in the schematic I have, which would make trying to guide someone through any possible further fault finding tasks rather difficult. Plus the pins on the processor chips are very close together and so a thin probe and steady hands are need to prevent shorting out adjacent pins and potentially causing additional damage.