Gorf sound repair

[Riptor]

The problems I see with the gorf sound amp is the transistors and those two resistors. Replace the tip31 with a tip31C if you can, will hold up a little better.
Always meter those resistors. I have seen them look fine but are open and I have seen them burned to hell yet still be in spec. Wouldnt hurt to bump them up to 1/2w instead of 1/4w. Someone mentioned fusible resistor, are these in fact fusible?

 

[smashedtv]

will do...just gonna order from bob...wish he had a kit for this too....some of those small suckers have impossible numbers to read on the copied pdf online...nice cursive sheesh

 

[ELutz]

The problems I see with the gorf sound amp is the transistors and those two resistors. Replace the tip31 with a tip31C if you can, will hold up a little better.
Always meter those resistors. I have seen them look fine but are open and I have seen them burned to hell yet still be in spec. Wouldnt hurt to bump them up to 1/2w instead of 1/4w. Someone mentioned fusible resistor, are these in fact fusible?

To my knowledge, they are not fusible resistors. I've also seen the tantalum cap(s) die on that audio amp board with some frequency.

Edward

 

[Riptor]

Yeah, I didnt think they were fusible. Look like a standard 1/4w to me and I dont recall the manual saying anything different. Interesting about the tantalums. I have fixed a ton of these and never seen a tantalum bad on one.

 

[mcandrewsoun]

I second the tantalum cap.. The will make a dead short across the rails.

 

[smashedtv]

just placed my order with bob....wonder what extra goodies ill get this time....my first order i got beads, moon pies and coins lol

 

[smashedtv]

got my parts in today. the values dont match up on the wiring diagram vs the drawings for my stereo amp just like the one pictured. i have the a082-90983-a000

i was gonna replace the r3/r6 with 2 ohm 1 watts like suggested but on the schematic that has values handwritten it looks like r3/6 are 3.3u 1w...i did order the 300 ohm 1 watt resistors also and the tip31cs. bob forgot my kemet 15uf any suggestions why the wiring diagram would not sync with the schematic on page 54 middle shot

 

[smashedtv]

ok to keep you guys up to date...last night replaced the 330 resistors and the tip 31s with 31cs....no change

My game initially to rehash had a blown 2a slow blow fuse on the power block--replaced it and did a bob roberts kit on the ps replacing all caps and diodes.....still no sound back

voltages check out at the cage..any thoughts..trouble shooting ideas

 

[smashedtv]

alright still no sound and ive replaced nearly all the parts on the sound board. anyone know if the kemet capacitor can still be purchased. im looking for the 15 mfd one. the manual does not specify the volts either....thanks

 

[smashedtv]

ok little help here please...nearly all parts on the audio amp have been replaced. so I went back to the beginning and found my slow blow fuses are popping. Anyone know what voltage I should be getting at that point and how to fix it?

Ive done a Bob Roberts repair replacing all caps and diodes on it. If I knew which voltage I should get where I know we can fix this thing. The sound used to work on my machine

thanks

 

[orion3311]

Maybe try a different speaker? Although rare they do go bad, especially if the amp did fail at some point.

 

[smashedtv]

thanks man..i will unhook them and test their impedance and make sure they work well from an off game source..doubt they are the culprit though...i just need to know the primary reason that the slo blow fuze goes on the right side

 

[smashedtv]

ok went back to my audio amp as my mind is not on daylight savings time...I found a solder connection at the pins where two were touching. desoldered and viola...have sound and no fuse blowing..but...a loud hum and only partial left channel sound. maybe the diodes bob gave me were wrong i changed..dunno.,.any other ideas

would that cause the hum...I have garbled sound for shooting, effects and such..just hum out of the right side