Revox B77 query
 

Hi all, I’m in the process of renovating a B77 HS I’ve inherited. I have come across a very weird problem though.
On the Tape Drive Control PCB I am missing a chip. IC2 on the schematic has been replaced with a mares nest of wires (they look like fine telephone wires). They have been cut so have no idea how they connect. So, I’d like to revert the board back to standard. The manual quotes a part number as:
IC2 = 1.177.317.51 PROM 32 X8
I presume this is a Progrmable Read Only Module? If so, where can I get a replacement from? I’ve not come across this before so am stumped. Anyone have a suggestion?
Mike

Re: Revox B77 query
 

Hi, if you want is I have one of the IC PROM 32x8 of type N82S123N.
I ask for that chip 50 euro without shipping.
Shipping is about 5 euro.

Jack Marotick

Re: Revox B77 query
 

That board and later ones are as far as I know interchangeable, so my advice to you is get yourself another board.

Re: Revox B77 query
 

Hi Jack, thank you for your offer but I think it more cost effective to look out for a replacement board complete, as has been suggested. Mike

Re: Revox B77 query
 

MkI and Mk II use different transport boards - the later type has a more benign take-up on starting.

Re: Revox B77 query
 

Hi all, I’m now very confused.
I’ve tried a board out of a PR99 and all works ok. I’ve got a spare TCB (I’d forgotten I had it previously) and put that in and I still have a problem. If I turn the machine on with no tape all is well. If I turn it on with tape loaded it immediately goes into play and runs. If I stop it all is well again and it works normally.
I’ve checked the caps C16 and C17, both are in spec. I’ve changed the IC4 and it made no difference. Now I’m stuffed. Can anyone suggest what the problem is?
The fault is there only when turning on with tape loaded and after then pressing stop all reverts to normal. Everything else is good and within spec.
Help!
Mike

Re: Revox B77 query
 

Sounds like the timer mode is on so tape will run as soon as powered up

Re: Revox B77 query
 

I used to have a REVOX B77 1/2 track stereo 7.5 / 15 ips back in the late 70's early 80's.

In the early 90's it required some attention and I found a place nr Manchester Airport who was the local repair agent for Studer / Revox. I took the unit over to him and he did an excellent job at what I did not consider an excessive cost.

I found a google hit for him just now at Brian@RevoxService.co.uk.

Might be worth a try for info' or more if all else fails.

I should say that I have no connection with his business, apart from using his services back in the early 90's

Re: Revox B77 query
 

...and of course there's Michael Maurice (above, post 3) who would be nearer.

Re: Revox B77 query
 

There is no timer function unless you are using a remote control.

The transport board may be different for a PR99 as it would have to work with other boards such as the counter and zero locator etc.

Re: Revox B77 query
 

I've used a PR99 board in a B77 successfully, but it was from a Mk I with the mechanical counter.