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Hi all. I've got a 1090 and I'm checking out the rear panel board. The QV06 diode is shorted and I'm looking for a replacement. The SM says that QV06 is a W06B. Can I trust the SM in this case? Is a 1N4005 a valid replacement for a W06B in this circuit?

Huge help and just in time! I assume you had to jumper the other side?

Awesome. Thank you.

Hi guys. I'm having trouble finding in stock replacements for the main caps in the 1090 power supply. C809, C810, are rated at 6800µF/50V. I've seen a few couple rebuild threads of this model but the caps used are no longer available. Appreciate any suggestions.

Pioneer SX-434, Pioneer CS-A700, Tannoy Cheviot

Ahh good to know. I dont know if the right channel has had blown outputs but it wont hurt to pull the resistors and test/replace them. Thanks for the knowledge share.

I've been seeing more and more suggestions from veterans to take a modular approach to restoration. I'd like to learn more about this. It seems like the most logical approach to start at the beginning, get one section working to spec and move on to the next. I'm not sure how to isolate the...

Forgive me if I make any incorrect statements here. And if I do please point them out! I've been practicing schematic reading lately. I believe the emitter resistors in this unit are (Left) R763, R765 (Right) R766, R764. Schematic Attached. I've replaced R763 and R765 with some wirewounds of...

Honestly it hadn't occurred to me to hook it up. I've been struggling with a short in the left channel that seems to have be fixed since im no longer smoking outputs. Never thought to take it for a test drive. So I did. The right channel sounds better than the left. The right has some...

The measurements for idle current for the left side change when i turn R771. The right side does not change when I turn R772. I did change those trimmers out. I used leestereo's 1090 rebuild for suggested trimmer replacements

Hoping you guys can direct me to figuring out an idle current issue with my Marantz 1090. The left channel looks OK (after replacing some smoked components). I'm measuring 11mV across the emitters on the left channel. But on the right channel I'm measuring 0mV across emitters. I found this...

OK. Trimpots are replaced smoked resistors have been replaced. Electrolytic caps on the power amp board have been replaced (per leestereo's 1090 rebuild thread) New output transistors have been installed I brought her up on the DBT and no smoke! From the advice you guys have given it sounds...

I believe these are original replacements. I bought these specifically: https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F282493511228 https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F290843707715

I agree, something is definitely amiss. I've ordered new output transistors and they should be here next week. In the meantime I'm going to start replacing the caps in the power amp board just to be safe. Should I pull the smaller transistors from circuit and test those as well?

I appreciate the offer Wolfman. I've downloaded a copy of the SM. The service manual has a section for "Adjustment of Idling Current" that goes like this: Connect a vacuum voltmeter to between emitters Q721 and Q723. Adjust R771 until 12mA is reached. Likewise, adjust Q724, Q722 and R772...

Headphones did sound OK. I didnt have the heatsink installed. I dont clearly understand the relationship between the bias adjustment and the DC offset. I did find a tutorial to measure the DC offset and I did that. Not sure how to measure the bias though. Not having a frame of reference I...

Well scratch all that. I put the outputs back in and powered up on the dim bulb. This time the bulb stayed bright and the left channel smoked. Burned up a few resistors in a matter of seconds. Guess im back to the drawing board and way in over my head with this one.

OK She seems to have passed the dim bulb test. Creating that device was fairly simple. I used a 60W incandescent bulb in series. When I turned the amp on the light flashed bright and dimmed quickly then went out. I've replaced the fuses brought her up for a test run on headphones. I'm...

Good catch. I actually ordered the trimpots and forgot to swap them out. Also good catch on that resistor. It measured within spec but upon visual comparison to other 1090's its definitely changed colors. Is there any way to test the unit out without blowing the output transformers (in...

Thanks for the vote of confidence Mike. I need all I can get. Do you have any advice on post repair start-up procedures? Anything I should try before firing her up?

Here's the repaired main amp board. Had a little trouble with pads lifting in previously repaired areas but otherwise no issues. Im going to put it back together and see if it will fire up. Any tips? Should I try headphones first? Connect up to sacrificial speakers? Measure speaker output...

Lastly for repair part ID's: these transistors. From my reading these are pretty rare but can be found on www.littlediode.com If I've tested these correctly they're shorting between the emitter and collector and need to be replaced. Blue is a NEC B618 and Black is a NEC D588

Thanks for the suggestion. I'll go with those. Not sure why I didnt see those in my search filters on mouser. I must have had a filter on 50V or something.

almost done with my list of repair parts. On to capacitors, or capacitor rather. This guy got fried by the neighboring resistor that flamed out. I've also attached a pic of an original that isnt fried. How does this look for a replacement...

Can you guys give advice on suitable replacements for the cement resistors on the emitter side of the output transistors? The parts list has them at 470 mOhm 10% 2W. Cant say I know much about emitter resistors at all.