Tape Trail

Reel to reel, cassette and other analogue tape formats.

Return to Tape Trail

Message Sort: Post Order or Asylum Reverse Threaded

Revox a-77

50.200.188.134
Posted on January 27, 2015 at 16:30:44
6bq5
Audiophile

Posts: 4385
Location: SF Bay
Joined: August 16, 2001
 I recently picked up a Revox A-77 from a guy who bought is as part of an estate sale package - (he also picked up an MR-74, C-28, MC2105 and a pair of ML-1 speakers)

The Tape Deck has not been turned on in a while - few years? not sure-
What should I do PRIOR to plugging it in,
and then turning it on?

I recall that the Revox has some electrolytics in the signal path - and so take a day + to fully charge to make sound come out..
Any help would be appreciated...
Happy Listening

 

Hide full thread outline!
     plug it in - michael22 19:27:23 02/01/15 (3)
       A700 - Inmate51 07:20:33 02/05/15 (1)
         RE: A700 - michael22 21:20:00 02/05/15 (0)
    ...
RE: Revox a-77, posted on January 28, 2015 at 05:41:44
Dave Pogue
Audiophile

Posts: 11689
Location: DC Area
Joined: October 9, 2001
 I had one like that, the final (Mk IV) version. First thing that happened were some exploding capacitors. My tech calls them "firecracker caps." Then it caught on fire. Luckily went out by itself. I ended up deciding it wasn't for me. I'm too technically illiterate to point out which caps were involved. Good luck with yours, seriously. Many folks love them.

 

RE: Revox A 77, posted on January 28, 2015 at 06:51:29
Inmate51
 Do a Google search for something like "revox repair in Nashville". That's where the heart of Studer/Revox was back in the tape recorder days.

Also, contact www.revox.ch in Regensdorf, Switzerland for advice.

:)

 

RE: Revox A 77, posted on January 28, 2015 at 09:47:24
mcgjohn@yahoo.com
Industry Professional

Posts: 501
Location: Midwest
Joined: February 5, 2008
 6bq5,
There are 3 options you have.

1. the best option would likely be to plug the deck into a variac and bring it up slowly over several hours to line level. If the caps are not completely dried out, this will give them a chance to reform a little before being hit with the max voltage they will see in their circuit.

If you don't have a variac, wire a 100 watt light bulb in series with the hot line going to the deck. it will act as a crude current limiter.

2. just plug in the deck to an outlet and flip it on. See if caps 'firecracker" off, unplug the deck, and at least you will which ones were weak, and need to be replaced. Be sure to clean up any residue from the exploding caps since it will be corrosive and over time can attack the PCB board or other components it came in contact with.

3. replace the power supply filter caps before plugging in the deck. With fresh caps, that will minimize the likelyhood of caps going off.

The audio coupling caps, if they are bad, likely won't firecracker off. You will just get some hum that comes through them.

Best of luck. The A77 is a nice deck, and was well built.

J

 

RE: Revox A 77, posted on January 29, 2015 at 11:44:47
6bq5
Audiophile

Posts: 4385
Location: SF Bay
Joined: August 16, 2001
 Thanks ALL-
I have some work ahead - but looking forward to getting this upo and running!
Happy Listening

 

plug it in, posted on February 1, 2015 at 19:27:23
michael22
Audiophile

Posts: 917
Joined: October 1, 2001
 Plug it in, turn it on, and see if it works. But stay near it and see if anything starts to smell. Mine started to smell, then smoke (no fire, luckily.) I put in on the bench, opened it up, and identified the bad cap. It was pretty obvious. I replaced all three of the same type and the machine now works fine.

BUT ... the same thing happened to my A700 and now have to deal with that baby.

I'll post again with more details on which caps to replace.

 

.47 microfarad caps, posted on February 5, 2015 at 07:03:13
michael22
Audiophile

Posts: 917
Joined: October 1, 2001
 To be more precise, the problem caps are C113, C113 and C115 on the tape drive control board. These are 0.47uF 150 V metalized paper caps. I substituted 400 V which worked fine.

 

A700, posted on February 5, 2015 at 07:20:33
Inmate51
 In 1974, when the A700 was brand new, I had an opportunity to use one for a few weeks. I didn't like it, mainly because of the somewhat 'flimsy' construction of the controls.

Just my opinion.

:)

 

RE: A700, posted on February 5, 2015 at 21:20:00
michael22
Audiophile

Posts: 917
Joined: October 1, 2001
 flimsy controls is an understatement. all of the slide control handles on mine have broken off. not a good design. but the machine has performed well and generally sounds good. i bought mine for $15 at a local thrift shop. it came with an RCA 2-track classical tape that i sold for $30.

 

Page processed in 0.023 seconds.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]