Reel to Reel Tape Deck Restoration

[almandog]

Hello:

I have a question:
If you want to do a complete restoration of Reel to Reel deck what would be your method approach of in doing it?

I am not just talking about recapping the the deck, I mean servicing/replacing everything that's not nailed down: reel motors, capstan motor, tape path, components, devices, etc...etc... And let's suppose it was a Revox A77, B77 or PR99; what would be your sequence in doing this restoration to make this deck brand new again?

 

[KentTeffeteller]

Full rebuild from the ground up in most cases. All the ReVoxes tend to need extensive servicing to get to specification when new. Not an easy or short process. Every Rifa, Frako, and Philips capacitor needs replacement, most trimpots need replacement if not all, A 77 machines often need brake bands, heads not unusual to need replacement. None cheap. Electronics and brakes and sometimes heads most likely to need attention with age.

 

[almandog]

Kent:
The question is: How would proceed in doing this rebuilding? What would you do first, then next...... don't get down into the weeds. Just stay at the high level.

 

[Tinman]

Oh look, our new "tech" has found this forum as well.

You ask some weird questions for someone who has already done a bunch of decks.

And to answer your question, it depends on the deck itself. There is no set in stone rule. Fix whats wrong first, THEN overhaul as you wish.

The end result is the same.

 

[twiiii]

Unless you are familiar with R2R tape decks I would look for a professional to restore your deck. I used to repair Revox A-77 and B-77 along with Professional Ampex, Crown, MCI, Studer and consumer Ampex when I was in-between other jobs. I still have a B-77 which I went through one last time 15 years ago while dubbing my recordings to CD. I still have two professional Ampexs and one consumer machine. Ampex s are so much easier than Revox. You will need test equipment and alignment tapes and with out them you are barking up the wrong tree and doomed to fail. Service manuals are very essential, too.

 

[almandog]

TinMan:
I was on this forum before but moved around. The more the merrier. Plus there are different people and opinion on each forum. I did a few decks but I am still a newbie. Se ready to learn.

Any way that's just my point: if the deck is going to be done from ground up, why fix it first when all components are going to be changed out? I see the logic in fixing it first if something is wrong, before a recap. But not if you are doing a total rebuild. Am I missing something?

 

[Tinman]

Yes, you are missing something. We amke mistakes! (see what I did there)
The idea is to know a state of a machine before you rebuild it, so if you DO screw up, you have a reference to go back to.

In MY case, I CAN just rebuild a deck outright from the start, but that's only because I have done so many.... ugh... and I basically know them inside and out.
So if I make a mistake, I know where to look based on that experience. What.. 40 years?
And even then, there are often hidden "surprises". Most of those are usually caused by previous "techs".

In your case, as with the A700 which I purposely stayed out of... you should take it in stages as you learn. At some point you can just "know" symptoms and what causes them. However, this is best learned by doing it. Not being told what to do.

Personally, I re-cap, then pots, then test the machine, and then do all the bearings, etc, then test again, do all adjustments, and last do all the calibration.

And I also discovered which machines will cause you more problems than they are worth in YOUR time and what a customer is willing to pay.
I have had to tell customers, and I quote: "Just because YOU can buy a DVD player for $29 DOESN'T mean that "I" can fix it for $5!
Labor time, (Literally your FINITE LIFE) doesn't get cheaper with technology, nor do the parts.

So don't take on just any machine. It's a death trap. Stay away from rare and exotic machines unless you are sitting on a pile of spare parts for them.

The A807 and C model decks come to mind. Sure, you can re-cap one, but god help you it needs a cosmetic or mechanical part. THEN the fun starts.

Etc, etc. You learn to pick your battles as this stuff gets older and increasingly rare. The A700, B67 and even the A77 are decks that fall into the "it's really only worth the time if you aren't paying for it" category. Yes, SOME customers will pay your asking price, but remember.... these decks like to keep failing.... and YOU are now attached to them for the implied or otherwise warranty period.

But that isn't your original question, but something you WILL run into.

In the end, you will eventually tailor your work flow to what works best for YOU. Same with the equipment you collect to do that job.

 

[almandog]

Tinman:
That's one of the best response I have ever got from any posting, and one that really pointed out the ins and out at a high level that I was looking for. Thanks for your thoughts and pointers on tape deck repair in general.

When I first got started with this hobby, I collected a few different decks just to learn about tape decks, and in so doing i have narrowed down my deck interest to Revox A77, B77, and PR99. I have worked on Tascam 32, Teac, and Pioneer RT909. But the Revox are much easier to manage so those are the ones I will be doing.

I agree with your logical approach in performing repairs: Diagnose, repair, test, then calibrate. Makes a lot of sense to me. With respect to customers, I do not take on repair jobs. I do it for myself, and sell the deck only when it is ready, so I have to take my time. Labor cost is higher than a deck is worth in some cases, so I stay clear of taking on jobs.

Thanks again for your thoughtful post.

Mando..

 

[Tinman]

I didn't take on repair jobs either.... it sort of "happened" after I talked about my hobby. It slowly became a "job".

So don't hold your breath. Before you know it, you could be the Hawaii tape deck guy!

 

[SaSi]

Here's am amateur's approach. I'm no tech by any mean of the term, just an educated amateur with some experience. Especially with the B77/PR99 machines.

First, make sure the deck is functional. If there's something wrong, keeping it from performing the expected functions, play, record, FF/REW, they need to be fixed.
Recapping is for a later stage, except for some ... exceptions that are native to Revox (RIFA).
Then, for my taste, comes the time for a mechanical overhaul. In the case of a PR99, it meant a total stripdown, cleaning, relube and re-assembly. It was a functioning unit that came out of a smoking environment so everything inside was covered in tar. Down to removing the main audio board, cleaning pads and switches and pots.
The motor bearings need to be looked at (or not) depending on their condition.
Then come the boards and re-capping. In some cases, capacitors need to be replaced during an initial troubleshooting stage. They sometimes are responsible for non-functional or erratically functional units (although it has happened to me in my brief experience on a turntable and a cassette deck only).
Then comes the heads. If they have small wear, they can be relaped. Otherwise, replaced. On my PR99, I replaced them with Nortronics heads after the recommendation and some good guidance of the owner, Joe Dundovic (RIP). The heads I got sound terrific and hold up pretty good compared to Revox heads, especially considering the punishment of 15ips.
With Revox decks, it's a good idea to replace at least some of the trimmers. Some replace all of them. I had to replace 3 on a B77 due to erratic contacts.
Adjustments and calibration are the last things to do. As per the manual. Getting hold of the proper calibration tapes is a must.
The tools needed include a couple of DMMs, a needle mV meter, a scope and a function generator (although I don't use one, I use my PC soundcard and s/w).
For tension measurement, a tentelometer is also needed.
A spectrum analyzer is also very useful for measuring distortion, and I make do with my PC and Audition. It's much better than a low end digital scope spectrum analyzer.

 

[almandog]

Tinman:
Yes you could be right. One thing leads to another. Actually I get several inquiries about repair cassette decks. I turned it down. I have a Teac cassette deck that I bought new in 1984 and it is still working. I never even change a belt. And I wonder if it uses belt or not. I never opened it. Never needed to.

SaSi:

Can you give me the link for the new Revox heads you mentioned?
Your approach to the restoration is also sound. I do have all the test equipment you mentioned and also MRL tapes (15ips and 7.5ips). I will proceed with caution in doing my next PR99, A77, and B77.

 

[GPS16]

Hi Almandog,

I have had reel to reels of some sort or another since childhood, thanks to my Grandad. I bought a Pioneer RT707 when I left school and wore it out. This led me to the Revox B77, A700 and C270 path. I cut my teeth on the B77. Liked what I saw and was dealing with. The next machine was a A700 is pretty good fettle. Then bought a dog (as spares). The dog got refurbished too. Due to the Specific Silicon in the A700, a C270 then came next. Payed a lot for that one as I knew it's history. Then got a dog C270 (as spares). This has now been refurbished and had 4 Track Heads fitted. I wonder if I have the only 4 Track NS (3.75/7.5 IPS) C270 on the planet.

In each case I played with them with a tape I did not mind losing to find the decks needs and deficiencies. Any mechanical issues were then addressed (if possible). I did not see the point of doing a re cap on a deck that was mechanically un-sound!! When I was happy with it mechanically, the next step was Electrolytics and Rifa caps (the smoke bombs). Then followed with the pots, where necessary! The small footprint ones seemed to hold up. The larger ones as used for Bias were changed on sight. They did cause problems no matter how well cleaned up.

When I had a runner, then came the expense of a MRL reference Tape or two. The required instrumentation I already had as I am an Equipment Engineer in the semiconductor industry.

Now calibration is an easy step to contemplate.

Well there is my Three Peneth!!

Cheers.

GPS16

 

[trisho0]

Adjustments and calibration are the last things to do. As per the manual.

I have the Revox B77 MKII and started with the overload indicators light adjustments but I don't see the 6 DB from the VU-meters as per the manual.
Also, the manual doesn't tell me what signal to inject in AUX RCA Inputs. I am not a technician but some skills with.

 

[Numone]

Personally, I’d send it to a Tinman and be done with it. Just putting aside the Electronic Engineering expertise on needs to have, all the equipment one needs, the alignment tapes, the specialist tools... so unless you have the EE expertise and you’re prepared to invest in the equipment, just forget it.

 

[trisho0]

Personally, I’d send it to a Tinman and be done with it. Just putting aside the Electronic Engineering expertise on needs to have, all the equipment one needs, the alignment tapes, the specialist tools... so unless you have the EE expertise and you’re prepared to invest in the equipment, just forget it.

I am facing to another question myself about the B77 tape machine. The Overload issue can be adjusted later. I found today the VU meters have an intermittent problem. Left channel sometimes drops signal coming from the preamplifier. I swapped cables and the Right channel presents the signal loss. So, I will have to check the preamplifier Outputs 1 and 2. The B77 always was hooked the cable from the preamp Output 1. I will have connect the output cables from preamp Output 2 to check. So, I will see this coming week. As a new member of AK am I allow to ask Tinman for repairing the B77?

 

[Numone]

If you’re in Los Angeles, why not? If you’re in a different city, state, country or even, continent, I suggest looking for “a” Tinman, IOW, a highly competent and respected R2R technician who can repair your ReVox. We have four TEAC R2R’s and whilst I can now competently undertake servicing items, such as lubing, cleaning, replacing service items such as brake felts etc., I leave electronic fault-finding, mechanical setup and repair, recapping etc. to my trusted R2R engineer.