UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players

Notices

Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

Closed Thread
 
Thread Tools
Old 15th Aug 2018, 8:37 am   #1
NorfolkDaveUK
Banned
 
Join Date: May 2018
Location: Norwich, Norfolk, UK.
Posts: 605
Default Revox A77 Record relay.

I'm struggling to understand what's happening (and what should happen) with the record relay, it's not engaging / activating .

It started with no audible input on channel B.

I did the usual track with the scope and I have audio going in and out of the input board, input going into the channel A record board, nothing going in to the channel B board. I checked the relay and it's not closing . I have checked the voltages on the relay board and I have the following with the record switches pressed:-

4 = 25v
5 = 25v
8 = 0v
9 = 21v
10 = 0v

Would be grateful for some advice 'm not really getting what should be happening with the rec buttons pressed . If I'm reading the schematic correctly there should be 0v on pin 5 and 20v on pin 8 ?!?
NorfolkDaveUK is offline  
Old 16th Aug 2018, 12:15 am   #2
Michael Maurice
Moderator
 
Michael Maurice's Avatar
 
Join Date: Feb 2006
Location: Wembley, Middlesex
Posts: 7,219
Default Re: Revox A77 Record relay.

I take it you are referring to the record boards A & B.

If you've got nothing going into Ch B board then the fault lies between the input board and the channel B board.

The record relay grounds the bias oscilator and rec amplifier output when the unit is NOT in Record and supplies 21V to the oscillators soft start power supply when IN record.

By record one or both of the channel rec buttons either side of the VU meters must be in and the record and play buttons pressed in to activate record.
__________________
Forum Moderator

http://www.michaelmauricerepairs.co.uk/
Michael Maurice is offline  
Old 16th Aug 2018, 9:08 am   #3
NorfolkDaveUK
Banned
 
Join Date: May 2018
Location: Norwich, Norfolk, UK.
Posts: 605
Default Re: Revox A77 Record relay.

Many thanks. All sorted now.
NorfolkDaveUK is offline  
Old 16th Aug 2018, 7:09 pm   #4
Michael Maurice
Moderator
 
Michael Maurice's Avatar
 
Join Date: Feb 2006
Location: Wembley, Middlesex
Posts: 7,219
Default Re: Revox A77 Record relay.

What was wrong with it?
__________________
Forum Moderator

http://www.michaelmauricerepairs.co.uk/
Michael Maurice is offline  
Old 17th Aug 2018, 11:01 am   #5
NorfolkDaveUK
Banned
 
Join Date: May 2018
Location: Norwich, Norfolk, UK.
Posts: 605
Default Re: Revox A77 Record relay.

I bought this used spares or repair and someone had been in there before me an mis wired the audio connect board . I`ve still got more issues to sort out but I`m getting there with it . Just need to find a VU meter that doesnt cost £40 as they do on ebay . I`m in no rush .lol
NorfolkDaveUK is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 6:51 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.