My Jaguar has Lost All Power

[Legtendga]

I recently picked up a working Jaguar and began buying games for it. It worked for about 2 weeks before it lost all signs of life. No power light, no electric hum, nothing.

 

 

As you can see, it doesn't seem to be the usual blown U38.

I've had no luck diagnosing the problem, and it happen so suddenly that I'm at a total loss.

Here's so more images to hopefully help analysis.

 

 

 

 

-On a side note, I'm having the same problems with my Heavy Sixer.

Edited September 9, 2013 by Legtendga

[+Stephen Moss]

Interesting that you are having the same problem with your heavy sixer. If the problem occurred with them at the same time it may point to a common problem such as loss of power to the wall or gang socket they are connected to (if the same).

 

Otherwise start at the beginning, can you check what voltage you have conning out of the respective power units? When disconnected from the console should be around 12-14V DC

 

If they seem OK then with the consoles switch in the on position check that voltage is available from the power switch, if that also checks out OK then it sounds like the power circuits may be fried.

[Legtendga]

Ok, both my 2600 power supplies as well as the Jag's are outputting fine.

The Jag is getting power over the On/Off switch aswell. D:

But my 2600 is now actually putting an image on the screen, it's just snow, though.

[Legtendga]

But my 2600 is now actually putting an image on the screen, it's just snow, though.

Well, it was....

[+Stephen Moss]

Not sure I can help much with the VCS as I don't have a circuit diagram. If you don't have one for the Jaguar you can find one at http://www.mdgames.de/jag_eng.htm

 

With a Jaguar cartridge inserted and the switch in the on position what voltages do you get at the following points...

1) Across R168

2) Between GND and any point that should be at VCC

3) Between GND and pin 8 (Vin) of REG1 (LM78L05ACM)

4) Between GND and either TP6 or pin 1 (Vout) of REG1

 

Interesting avatar, you were not actually using the Jag like that were you?

[Legtendga]

i plaid jagar laek taht tel it brake then cri :'(

[it's just the empty shell after I took it apart to fix it. The 32X is also not working though. -_-]

 

Anyway,

1) 1V

- After testing this connection, the power light will sometimes flash on if the cart is in the right position.

2-4) ... Pardon my newbie-ness, but I couldn't identify much beyond that on the board. Not to impose, but if you could repost my one of my pictures with the areas I need to test obviated, I'd be able to do so with confidence.

[Rex Dart]

All fled, all done, so chuck it in a fire; The math is done and the LEDs expire.

(with apologies to Robert E. Howard)

Edited September 10, 2013 by Rex Dart

[+Stephen Moss]

Anyway,

1) 1V

- After testing this connection, the power light will sometimes flash on if the cart is in the right position.

With the cartridge correctly inserted I would expect you to get the supply voltage across R168, the fact that you say the power light sometimes comes on with the cartridge in the right position suggests the problem may lies with the power feed through from the main PCB to the Cartridge and back but do the other tests I mentioned as well they can help with clarification.

 

The are several causes for the power feed through problem....

 

1) Incorrect cartridge insertion (a common problem amongst new users)

Try using two hands placed evenly on the cartridge when inserting to ensure is goes in straight as a slight tilt can occur that can prevent the power feed through from the cartridge PCB to the main PCB. If it is not to worn a slight click or feel of going over a bump/past an area of resistance should be heard/felt when fully inserted.

 

2)

Damaged or dirty cartridge / cartridge connector contacts.

Visually inspect the contacts for signs of damage or misalignment & dirt/tarnishing.

 

3) Dry solder joint on cartridge connector.

Can be hard to spot visually, only solution is to reheat the joint

 

2-4) ... Pardon my newbie-ness, but I couldn't identify much beyond that on the board. Not to impose, but if you could repost my one of my pictures with the areas I need to test obviated, I'd be able to do so with confidence.

If you look above the left controller port you will see two long thin yellowish Sill resistor packs, immediately to the left of those almost hidden by the two capacitors is REG1.

I would expect the big silver track around the outside of the PCB to be at GND (0V) but just to be safe pick it up from Pins 2-7 of Reg 1.

 

All IC packages mark pin 1 either by an indented circle immediately to the right of pin 1 or by an indented semicircle in one end of the IC package where pin 1 will be the first pin to the left of that. Pin numbers run are in sequence in an anticlock wise direction so for example an 8 pin device where the indented circle/semicircle is the "top end" of the IC Pin 1 would be top left, 4 bottom left, 5 bottom right and 8 top right.

[Legtendga]

5V between pin 1 and two, and 10V between pin 8 and 7.

 

I switched test games and now the LED is burning consistently. Also, R168 has 10V over it now.

 

I'm still unclear about what the VCC is, though.

[+Stephen Moss]

5V between pin 1 and two, and 10V between pin 8 and 7.

 

I switched test games and now the LED is burning consistently. Also, R168 has 10V over it now.

Those are the voltage I would expect to see, were the voltages between both pins 1 and 2, and 8 and 7 measured with the previous test cart or the one you have switch it with where the LED is on constantly?

 

Does it now work with the cart where the LED is on constantly or are you are still having problems even with that cartridge in?

I'm still unclear about what the VCC is, though.

As far as the Jaguar goes VCC is the positive (+5V) supply rail from the internal power circuitry (U38)for the main circuits (all processors, Memory and Video IC's), Audio VCC is the same thing but for the analogue audio output circuits (REG 1).

Traditionally Vcc and Vee represent respectively the positive and negative (or 0V/Gnd) connections for Bipolar semiconductor and Vdd, Vss are respectively the same but for CMOS semiconductors although there seems to be a lot of cross over usage these days.

 

You should be ably to measure Vcc at one end of L129 (font right side of the PCB) but a better place would be to measure the voltage across C159 which from you photos appear to be immediately to the left of L129.

[Legtendga]

Welp, the reason everything seemed so normal is there was a couple solder points in the RF Box that looked pretty shoddy, so I touched the up and it now works fine. The other game I was testing with still doesn't, though.

I express the utmost gratitude for your help and guidance in this.

[Legtendga]

...but about that Heavy Sixer...

[+Stephen Moss]

Welp, the reason everything seemed so normal is there was a couple solder points in the RF Box that looked pretty shoddy, so I touched the up and it now works fine. The other game I was testing with still doesn't, though.

I express the utmost gratitude for your help and guidance in this.

Iffy solder joints in the RF section may have prevented RF output but the unit should still have powered up assuming no problem with the power feed through from the cart, but at least it seems to be working now and you only have a potentially defective cart to replace.

 

...but about that Heavy Sixer...

I found some circuit diagrams at http://www.atariage.com/2600/archives/schematics_pal/index.html

 

Again we will start at the beginning, there should be a (LM)7805 voltage regulator, when looking at it the from it will have three legs going into the PCB, a black body section about 10mm square above those and a metal tab also about 10mm square protruding above that.

Both the metal tab and the centre leg should be at 0V (GND) the left leg should be the input and the right leg the output, with the power supply attached and the unit operating correctly the input pin should read about 9V DC and the output pin around 5V DC. What voltages are you getting at those points?

[Legtendga]

Ok, I believe I've test the correct points, and they read 3V.

 

Also, here some pictures (just 'cause):

 

 

 

 

 

 

 

 

 

 

On a side note, this part is heating up:

(Bottom left part, to clarify.)

 

I'm not certain if that helps, but there it is.

Edited September 22, 2013 by Legtendga

[+Stephen Moss]

Ok, I believe I've test the correct points, and they read 3V.

 

Also, here some pictures (just 'cause):

 

 

On a side note, this part is heating up:

 

(Bottom left part, to clarify.)

 

I'm not certain if that helps, but there it is.

Yes, that bottom Left part is the voltage regulator, it will get warm/hot under normal usage that why it is bolted to that metal Heatsink, if they overheat they can go into thermal shutdown where the output voltage will generally be about 3 volts although I am not sure if regulators of that vintage (assuming it is the original) had thermal shutdown. However, as you say you are reading 3V at both the input and output pins that suggest a lot of current is being sucked out of the main supply, probably due to a VCC (+5V) to GND (0V) short circuit.

 

It looks like the Power/Switch PCB is connected to the other(s) by a cable, did you measure those voltage with all the boards connect to each other or was the Power/Switch PCB disconnected from the others? If you measured those voltages while connected to the other PCB’s and it can be easily done try measuring them again but this time with the Power/Switch PCB disconnected from the others, that will tell you if the fault is on that PCB or another one.