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  1. Natalya

    Onkyo TX-SV525 with lots of issues!

    I'm assuming I can just check resistance of the board with the multimeter in the charred area? Am I seeing if it conducts to like the chassis, or just locally in the damaged area? And yes, there were some small cracks where the leads went. I don't have a photo of the back from after I removed...
  2. Natalya

    Onkyo TX-SV525 with lots of issues!

    I found some burned stuff. I'm not sure when this happened, but it was kind-of obscured by those ribbon cables. Here's the back of the burned area. The damaged solder joints turned out to be resistors. I removed the damaged resistors and two of the nearby capacitors. The bad...
  3. Natalya

    Onkyo TX-SV525 with lots of issues!

    Okay I had 2 transistors near Q673 (the one which was OL on all combinations) have 2 combos with values and 4 with OL. Are those two definitely blown then? Q526 and Q528, they're near Q673. Haven't had time to check all the diodes and capacitors in the area yet... but the big diodes are okay...
  4. Natalya

    Onkyo TX-SV525 with lots of issues!

    Okay so I removed most everything in the area of the components that set on fire. I also removed Q673 which is a transistor shown on page 26 of the service manual I linked in my post above, it says it's part of a PROTECT circuit. You can see the light coming through its 3 holes on the right in...
  5. Natalya

    Onkyo TX-SV525 with lots of issues!

    Found the service manual online. F901 near the lower middle of the diagram on the power board is the fuse that blew. Service Manual Link Here
  6. Natalya

    Onkyo TX-SV525 with lots of issues!

    Noticed something this morning. The fuse that blew was a 3A 250V fuse, but the board has written on it 6.3A 125V. I didn't have a 6.3A on hand but I do have a 6A 250V, so I put that in there. Tried to power on with lightbulb tester again. Same thing happens, light flashes as the relay...
  7. Natalya

    Onkyo TX-SV525 with lots of issues!

    7 months later I finally work on it. Removed burned B1557 transistor, replaced with new. Removed burned D2386 transistor, replaced with new. Both of those blew on the emitter side. When replacing I put Thermalcote I on the back. Three resistors had scorch marks. The big block one shown...
  8. Natalya

    Onkyo TX-SV525 with lots of issues!

    In the 1990's when I was a kid, after my dad's Pioneer SX-535 went bad he bought an Onkyo TX-SV525. Decades later I ended up with the SX-535 which I fixed with y'alls help. Thanks Audio Karma! Anyway, the Onkyo got passed onto my brother who kept it the last 5 or 6 years, but now it doesn't...
  9. Natalya

    Pioneer VSX-1020 Constantly Resetting -- is it Safe Mode?

    I've got two more stereos to work on recently. The first is a Pioneer VSX-1020. So, with absolutely everything unplugged from the back, if I plug it into the wall and press the power button: - I hear a click (a relay?) and it says, "POWER ON" - I hear another click and it flashes "AMP ER"...
  10. Natalya

    SX-535 Re-Capped, but Buzzing Returned

    Y'all got any thoughts as to like, why the output transistors went bad and blew the fuses to begin with?
  11. Natalya

    SX-535 Re-Capped, but Buzzing Returned

    I replaced the 8 transistors mentioned, and I replaced the 12 resistors mentioned, and the blown fuses and the stereo sounds good again! When replacing the 2W 0.5 ohm resistors I used 3W versions. Maybe that'll help if something goes wrong in the future? Thanks guys!
  12. Natalya

    SX-535 Re-Capped, but Buzzing Returned

    Hi, yes both channels blew their fuses -- F7 and F8 on page 6 of the manual. I'll order new resistors for the entire power amp board. I guess I don't know which are the output transistors vs the driver transistors. If you open the stereo, the power amp board has 4 transistors on a heat sink...
  13. Natalya

    SX-535 Re-Capped, but Buzzing Returned

    Hi everyone, after my last post in this thread, the stereo worked great for the next 2½ years! I set it up at the warehouse where I work and we used it to play records, listen to the actual radio, and we used it for audio from the computer -- usually music on YouTube. But, about 2 weeks ago...
  14. Natalya

    NIKKO 8085

    Just wanting to update that I got the fuse-lamps replaced with part # 070-120 from Parts Express. https://www.parts-express.com/8V-250mA-Fuse-Type-Lamp-070-120 They're not exactly the same specs as the originals, but they look nice. I replaced all of them at the same time, in case the other...
  15. Natalya

    NIKKO 8085

    I used a red LED to replace the disintegrated stereo bulb. I've also ordered the fuse lamps for the other bulbs.
  16. Natalya

    NIKKO 8085

    A friend of mine was impressed with how well my dad's old Pioneer SX-535 sounds after I fixed it, so he asked me to check out his Nikko 8085. Here it is opened up. DeoxIT fixed all the sound issues. A couple channels didn't work and the left sounded all staticy, but after spraying all the...
  17. Natalya

    Diagnosing Intermittent Dead Channel on a Power Amplifier?

    First, I want to thank everyone who helped me in my other thread last year. With the help from everyone here I was able to fix my '74 Pioneer SX-535 and I am convinced it sounds better today than it would have sounded the day it was built. ------------- This time I'm working on something a...
  18. Natalya

    SX-535 Re-Capped, but Buzzing Returned

    https://drive.google.com/file/d/1W8Y40oNGD1gk3BUoKUI5aW7Es7pKHdpo/view All right, I tried that on FM. The bulb fluctuates in brightness if the volume is turned up. I think I went to about 35% in this video. Is this looking ok or sketchy?
  19. Natalya

    SX-535 Re-Capped, but Buzzing Returned

    All right, I took a power cord and an extra GFCI outlet that I had laying around and a lamp and wired them together. I'm pretty sure I did it properly, with the lamp in serial with the hot line from the wall. I used a 75W Incancescent bulb in the lamp. Wall Hot --> 75 W Lamp --> Outlet Hot...
  20. Natalya

    SX-535 Re-Capped, but Buzzing Returned

    Okay two of the 1N4004 diodes behind those fuses were shorted, I've replaced them. I'll construct one of those lightbulb tester things before I try powering it on again. I checked the 4 big transistors on the power amplifier board, none of them were shorted from collector to emitter. Those...
  21. Natalya

    SX-535 Re-Capped, but Buzzing Returned

    All right, I put the spare filter cap onto the slot with the orange wires. I connected orange to negative and black to positive, as shown in the photo on page 2. Once again, SOME GOOD SOME BAD Speaker A and B switches OFF Volume 0 The Bad: I turned it on and the same 4A fuses blew, this time...
  22. Natalya

    SX-535 Re-Capped, but Buzzing Returned

    HOLY SHIT I can't believe they would do it that way, but you are right they had the wires switched in that one. GOOD THING I ORDERED 3 CAPS INSTEAD OF 2 JUST IN CASE!!!! I'll try reversing the poles on that one, but if it's toast I can put in the spare. Thank you so much for noticing that, it...
  23. Natalya

    SX-535 Re-Capped, but Buzzing Returned

    Okay I did the filter caps. SOME GOOD SOME BAD Good: - No more buzzing noise! It's gone! The noise was there the second one turned on the stereo, now it is totally absent. Yay! Bad: - I turned it on with the bottom still removed and the lid removed so I could see if anything funny was...
  24. Natalya

    SX-535 Re-Capped, but Buzzing Returned

    All right, I measured the diameter, they were 35mm. I therefore went with the 2nd caps you listed and got them in the mail a couple days ago. Anything I need to watch out for when installing them? I've never worked with capacitors this big. Y'all were right about the bleeder resisters, I...
  25. Natalya

    SX-535 Re-Capped, but Buzzing Returned

    Hey I looked at the resistors in the photo at the top of the page, between the leads of the big caps, they say 560ohm but I don't know like their wattage? Anyway, with a multimeter they're not reading 560 ohms, one is around 530 the other is like 270. I think I need to replace those too. I'm...
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