Atari Jaguar, no sound and only video on RF

[eightbit]

I have an interesting one. I received a Jaguar from guess where as "working", but that is only partially true. It plays games over RF (RF ONLY, not through the AV port) with no sound at all. I dug through forum threads and found this post:

 

 

 

I figured adding the bodge wire to see if I can at least get sound was easy enough and well inside of my limited skillset, so I did that however it did not bring back the sound. It actually made things worse. Which the wire attached from REG1 to the ADC (to pin 20, vcc...the drawing is wrong) I get a black screen when powered on. Take the wire off and we are back to picture on RF and no sound.

 

And, I ordered a Humble Bazooka Jag2SNES and using an HDRetroVision SNES cable and I get something a bit different, no video or sound...just a black screen.

 

I looked over the board for any of the usual damage you may see from plugging in an incorrect power supply, but I see no damage whatsoever. And, the console came in the box with the original power supply.

 

 

When I reported all of this to the seller he apologized, refunded me and told me I could keep the system and he didn't want it back. So, I am one up with a free somewhat working Jaguar. I have reached out to some different recommended repair people and am waiting to see what they say as I am more than happy to pay someone to have this repaired. 

 

In the meantime, has anyone seen these particular issues? I find a lot about either no sound or no sound and no video, but I can't find anyone where they were receiving video on RF but not on AV combined with no sound?

 

Edited April 2 by eightbit

[Stephen Moss]

12 hours ago, eightbit said:

I figured adding the bodge wire to see if I can at least get sound was easy enough and well inside of my limited skillset, so I did that however it did not bring back the sound. It actually made things worse. Which the wire attached from REG1 to the ADC (to pin 20, vcc...the drawing is wrong) I get a black screen when powered on. Take the wire off and we are back to picture on RF and no sound.

It is not a good idea to just do that without first establishing that the output from Reg1 is incorrect, because you then have two voltage regulators (REG1 & U38) fighting against each other as they both they and regulate the 5V supply for the who system.

12 hours ago, eightbit said:

And, I ordered a Humble Bazooka Jag2SNES and using an HDRetroVision SNES cable and I get something a bit different, no video or sound...just a black screen.

As you say that you are getting video on RF that suggest the video circuity is working, thus reasons why you do not get video through the Jag2SNES could be...

1. It is faulty
2. You have connected it upside down/internals were fitted into the case upside down thus the signals are not being routed to the correct place
3. When you say no video and audio with the Jag2SNES, is that just on the Jag2SNES output on does it kill the Jaguars RF video signal as well, if the latter that would definitely suggest an issue with the Jag2SNES as that should not happen. 

As for the sounds....

1. Have you checked that the sound is not turned down in the game setting?
2. Does pressing 0 on the keypad (mute/unmute make any difference?

 

If none of those solve the problem then you need to check the supply voltages to U10 (measure across pins 7 & 14) & U5 (measure across pins 4 & 5, be very careful not to short them with you meter probes), if they look ok then you you need to check the voltage on pins 5 & 13 of U10 (measured to GND).

Approximately 5V is OK, approximately 0V is not.

 

Otherwise, if those look OK it is difficult to debug the audio section if you do not have an Oscilloscope to check for the prescience of signals, but you can check the supply voltage to the audio output amplifier (measure across pins 4 & 8 ) to see if that is getting 5V power, if so and you do not have an oscilloscope to confirm a lack of output signal I would be inclined to change in case it has been damaged and is therefore not outputting any audio.

[eightbit]

4 hours ago, Stephen Moss said:

It is not a good idea to just do that without first establishing that the output from Reg1 is incorrect, because you then have two voltage regulators (REG1 & U38) fighting against each other as they both they and regulate the 5V supply for the who system.

As you say that you are getting video on RF that suggest the video circuity is working, thus reasons why you do not get video through the Jag2SNES could be...

1. It is faulty
2. You have connected it upside down/internals were fitted into the case upside down thus the signals are not being routed to the correct place
3. When you say no video and audio with the Jag2SNES, is that just on the Jag2SNES output on does it kill the Jaguars RF video signal as well, if the latter that would definitely suggest an issue with the Jag2SNES as that should not happen. 

As for the sounds....

1. Have you checked that the sound is not turned down in the game setting?
2. Does pressing 0 on the keypad (mute/unmute make any difference?

 

If none of those solve the problem then you need to check the supply voltages to U10 (measure across pins 7 & 14) & U5 (measure across pins 4 & 5, be very careful not to short them with you meter probes), if they look ok then you you need to check the voltage on pins 5 & 13 of U10 (measured to GND).

Approximately 5V is OK, approximately 0V is not.

 

Otherwise, if those look OK it is difficult to debug the audio section if you do not have an Oscilloscope to check for the prescience of signals, but you can check the supply voltage to the audio output amplifier (measure across pins 4 & 8 ) to see if that is getting 5V power, if so and you do not have an oscilloscope to confirm a lack of output signal I would be inclined to change in case it has been damaged and is therefore not outputting any audio.

 

It could be very possible that the Jag2SNES is faulty. I have no other AV cable to test. The HDRetroVision SNES cable works I know as I use it with a Super Famicom. And, I'm certainly not connecting it upside down. It does not kill the RF either.

 

When I say no sound, there's no BIOS sound. No roar, Atari jingle, etc. 

 

I think I'll be sending this one off to a professional for repair. Thanks though for your thoughts and advice!