Rotel RB-5000

[blhagstrom]

I have to open up the work area on and around my bench here.

People have brought Marantz 500, Sansui 9090DB, Concept 16.5, a couple Marantz 2500, etc here for work.

 

[Marantz Man]

Shhhh, keep the whole Rotel thing a secret. The TOTL stuff is still relatively affordable!
I have the RX-1603, RA-1412 and RA-1312 and I love them all.
Always dreamt of THE CONTROL AMP and THE AMP combo.

Good luck with your RB-5000 resurrection!

 

[blhagstrom]

:gigglemad:

Found one of these.
Broken diode that tests OK in circuit.
THESE are a real bitch! I've found them before. They hide until you unsolder them. At least this one did test "wrong" the last time through with the meter.

Amp adjustment now stable.

BUT, there is distortion in one channel and I think its in the OTHER amp.

The traces on these are delicate and the wiring is fragile so I skipped a deep analysis of the second amp. Looks like I have to go back in. I'll see what I can find with a scope first. They packed things in rather tight.

 

[Hyperion]

I am enjoying this too... thank you for posting your progress

 

[SPL db]

Nothing like listening to music using an arch welder for an amp! :thmbsp:

 

[blhagstrom]

Nothing like listening to music using an arch welder for an amp! :thmbsp:

And, just now it has that "arc welder" sound.
Just a little.
In one channel.

But, outside of that, :thmbsp:

 

[Mag84ilfully]

I have to open up the work area on and around my bench here.

People have brought Marantz 500, Sansui 9090DB, Concept 16.5, a couple Marantz 2500, etc here for work.

I recognize quite a few of these models

 

[slimecity]

I'd kind of written off Rotel gear in general until I saw this. Wow - Sensational looking amplifier and great work.

 

[blhagstrom]

Found it.

This WAS a replaced part. It got toasted because everything else wasn't working right.

Yes, its sounds as BIG and it looks.

I think I'm going to change my rate from hourly to by-the-pound!

 

[megasat16]

Found it.

This WAS a replaced part. It got toasted because everything else wasn't working right.

Yes, its sounds as BIG and it looks.

I think I'm going to change my rate from hourly to by-the-pound!

It's the reason I don't want to buy anymore Big and Heavy Amps! They are a pain to lift on the bench or remove anything for repair.

Hope that resistor is the last culprit in the RB-5000.

 

[Machineghost]

Good day! I have read the thread for a while now since I have a RB-5000 on the bench with very mild but persistent DC-offset. The DC-offset on the LEFT channel has been adjusted fully anti-clockwise and the offset measures are 1.4vdc.

I have replaced all the electrolytic capacitors (apart from the very large ones). Replaced the diodes at the DC offset circuits. Reflowed virtually every solder joint. Checked all the transistors in a tester. All check out. Tested the Input module on its own on the bench and its voltage points match up on both sides.

This resistor that you replaced... where was that located?

Your help and advice will be highly appreciated. Thanks.

 

[pjrengineer]

Good day! I have read the thread for a while now since I have a RB-5000 on the bench with very mild but persistent DC-offset. The DC-offset on the LEFT channel has been adjusted fully anti-clockwise and the offset measures are 1.4vdc.

I have replaced all the electrolytic capacitors (apart from the very large ones). Replaced the diodes at the DC offset circuits. Reflowed virtually every solder joint. Checked all the transistors in a tester. All check out. Tested the Input module on its own on the bench and its voltage points match up on both sides.

This resistor that you replaced... where was that located?

Your help and advice will be highly appreciated. Thanks.

did you get it worked out? Sounds like it’s time for some voltage measurements if you have a service manual.

 

[florianb]

with this type of amps can mop the floor with so called hiend amps like constellation audio or vitus