PIONEER SA-7500 0.01 150v Ceramic Cap Replacements?

[Segasonic91]

I am still battling to get my SA-7500 up and running after a backwards cap did damage that has kept it in protect.

I found 2 of the SR3AM-4 rectifier diodes were shorted and replaced them. Still no go. When testing with DMM set to ohms, I am getting a stable 10.7 on 2 of them, one is jumping all over and one shows as open. I want to replace the ceramic caps that are in line with those resistors as well as the one with the SIB01-02. I plan to replace those, also as again, 2 stable readings and 2 all over the place. I have already replaced output transistors and 2 of the 4 power transistors. Last thing, and I hope it is the last, is the 2 fuses.

I just bought a PIONEER SA-9800 (9500) from Japan so I want this thing done before it arrives or it may never get done!

 

[Hyperion]

I found 2 of the SR3AM-4 resistors were shorted and replaced them.

They aren't 'resistors' - they are rectifiers.

 

[Segasonic91]

They aren't 'resistors' - they are rectifiers.

Sure, those then. It was an error. Do you have any insight to my problem?

Is the modern OMRON MY4 02 24DC a direct replacement for the SA-7500 or does it need an adaptor?

 

[Segasonic91]

Let me put this another way, is it okay to put a higher voltage in this instance? The only 0.1uf caps I can find locally not less than 150v are 500v. I see some 150v on crapbay but they come with the usual pathetic US postage costs.

 

[avionic]

is it okay to put a higher voltage in this instance?

Yes ..

 

[avionic]

I found 2 of the SR3AM-4 rectifier diodes were shorted and replaced them.

Were these tested " in circuit". If they were. They probably were not bad.The bridged rectifier diodes need to be tested out of circuit.Due to power transformer secondary windings.If tested in circuit ---- 2 diodes will appear shorted.

Bridged rectifier is D5 - D8 SR3AM-4

 

[Segasonic91]

Were these tested " in circuit". If they were. They probably were not bad.The bridged rectifier diodes need to be tested out of circuit.Due to power transformer secondary windings.If tested in circuit ---- 2 diodes will appear shorted.

Bridged rectifier is D5 - D8 SR3AM-4

Thank you for the replies!

I tested them out of circuit. It was one of them that was shorted, not two. Sorry. I am testing the new ones in circuit so that wouod make sense that two of them test correctly and two jump all over the place? I've about lost my hair from this damn amp. All because of one silly, half asleep, mistake.

Everything in circuit where the wrongly installed cap that went "pop" is, tests fine. I do want to replace the transistors on that board as the ones with the heat sink and screw in the bottom of the board look dodgy. They most likely need replacing anyway so along with the zener diodes around the general area of the popped cap, that will be all I can do. After they are done and the 357's on the phono board are replaced, all transistors and caps will have been replaced and ALL resistors will be checked! I just wish to christ I knew were the goddamned short is.

 

[Segasonic91]

Changed the smaller diodes under the rectifiers tonight along with the zener diode in that area and still no click. Also replaced the power transistors.

Is it possible for the relay itself to have been killed by the popped cap?

There is a 1S2472 diode close to the relay, I will change that tomorrow as well.

 

[Segasonic91]

Nobody has any ideas for this "stuck in protection" problem?

I also would like to know if the relay can be killed by a popped cap that was in the wrong way around, and if the modern version with the same numbers is a direct replacement?