MrOneShotAway
New Member
Hope every one is doing good
.
Any way, I got my hands on an old Sony AMP, that's not super impressive with stats, but I would really like to get it back into working condition.
When I've connected it to power, the bulb lid up and it seemed to work. As soon as I connected it to a speaker, it started producing very large amounts of noise, and with a kind of loop that makes its amplification larger over time (matter of secondes).
I'm a really big noob, so I've tried Googling some things. Some posts suggested checking the transistors, so I did. The NPN once read around 0.53V B-C, B-E and the PNP's read around 0.6V too. The resistance for all transistors from E-C was okay, well at least it gave a large resistance and not something that is striving for a zero value. I've tried checking the speakers connections, and I've found out that the black connection, the minus one, at the B speakers isn't connected together. Maybe it's just an old wire, but what it's really that, how do I diagnose the problems?
Therse a dual C filter cap, that means it's a cap based on two capacitors that have the same minus lead (Parallel?). Do I need to change that big cap? and can I change it with two of the same value capacitor? I've tried searching for the dual c cap, but no luck...
Any way, I got my hands on an old Sony AMP, that's not super impressive with stats, but I would really like to get it back into working condition.
When I've connected it to power, the bulb lid up and it seemed to work. As soon as I connected it to a speaker, it started producing very large amounts of noise, and with a kind of loop that makes its amplification larger over time (matter of secondes).
I'm a really big noob, so I've tried Googling some things. Some posts suggested checking the transistors, so I did. The NPN once read around 0.53V B-C, B-E and the PNP's read around 0.6V too. The resistance for all transistors from E-C was okay, well at least it gave a large resistance and not something that is striving for a zero value. I've tried checking the speakers connections, and I've found out that the black connection, the minus one, at the B speakers isn't connected together. Maybe it's just an old wire, but what it's really that, how do I diagnose the problems?
Therse a dual C filter cap, that means it's a cap based on two capacitors that have the same minus lead (Parallel?). Do I need to change that big cap? and can I change it with two of the same value capacitor? I've tried searching for the dual c cap, but no luck...
![ba5a6692473796362dbf7c26f901671c.png](https://i.gyazo.com/ba5a6692473796362dbf7c26f901671c.png)
![5eb5ea1b9a080e872fa18f05a1e76b69.png](https://i.gyazo.com/5eb5ea1b9a080e872fa18f05a1e76b69.png)
![95afac1b29575453711c392e760a9e79.png](https://i.gyazo.com/95afac1b29575453711c392e760a9e79.png)
![dc692fbb72328ef6f8db9220ab27d05e.png](https://i.gyazo.com/dc692fbb72328ef6f8db9220ab27d05e.png)
![dd5cf5e182261116a17271556ab6bab8.png](https://i.gyazo.com/dd5cf5e182261116a17271556ab6bab8.png)