This will be by far the most controversial post on the website! After having repaired literally 1000s of pieces of electronics equipment, from fast food restaurant VHF belt packs for the drive-through system, to video projectors and reel to reels by the 100s, here’s my personal experience about fully recapping vintage electronics.
Far too often I read on Facebook and other online websites and forums ‘It’s a bad capacitor’, and while this can be true, there’s many times that it is not.
Theory and Reality
So, all capacitors are an electricity storage device. In this case, we are dealing with electrolytic capacitors in reel to reel tape decks. They are similar to a small (or large) battery and while we’re not diving deep into electronics theory here (there’s lots of that elsewhere online), we can touch on the basics. A capacitor stores electricity, and some high voltage ones can give you a good zap, long after the piece of equipment is turned off. (usually not the case with reel to reel decks).
So, just like a battery, a capacitor has two plates and some electrolyte and other chemicals that make up its composition. The ‘recappers’ claim that after 15-40 years (you fill in the number), the electrolyte fails, reducing the capacitance value (and ESR, but we’re not getting into theory here), and the piece of equipment in question is no longer in spec. In theory, that’s true. In reality however, things are different.
What a lot of people don’t realize, is that in general, the typical capacitor made back in the 1960s and 1970s was made a whole lot better than many capacitors made in the last 20 years. So, I stand here on my soapbox, saying that many, if not the vast majority of 40-50 year old capacitors are still well within spec today as compared to the day they were made. There, a very bold statement, and I’ll qualify it as follows:
Generally speaking, electrolytic capacitors were rated at +100/-20% in the 1970s. That means that a 100uF capacitor fresh out of the factory can read up to 200uF, and down to 80uF, and still be within specifications. There are other parameters of concern when dealing with capacitors, and not just the absolute value, but the bottom line is this: I use a high end Sencore brand capacitor tester to randomly test 50 year old capacitors, to see whether capacitors are good or not, and by and large, almost all of the caps in vintage electronics are still within spec.
There are additional tests that I do when it comes to capacitors. I do a full frequency response sweep (seen on all of my ads on Reverb, and sent to clients when a deck comes in for repair). A tape deck that has a capacitor that is well out of spec, either in the record or playback stages, will show that capacitor failure in the frequency response, or other manner within the deck. Assuming that the heads and overall operating condition of a reel to reel is in good shape, the frequency response should be very close between the two (or more) channels. If one channel has a capacitor that is way off spec, then the affected channel will have a different frequency response than the one(s) that is working properly.
Case in point: I recently had a high end Studer A810 mastering deck in for servicing. After a basic service (the client didn’t want to do the full recap at first), I saw on the frequency response plots that the left channel had a poor bass response. The one channel was flat to almost 40Hz (typical for a Studer), the left channel started losing frequency response around 100Hz, and by the time you got to 40Hz, the left channel was down 4db. That’s significant. I then checked the playback frequency response, and found it to be fine on both channels. It was the recording section of the deck that was causing the issue. I pulled both the left and right channel recording PC boards (they are modular in the Studer A810 for easy servicing), and found almost every electrolytic cap on the left channel board to be well out of spec. The right channel’s caps were also bad, even though the performance of the deck was still fine. I ended up doing a full recap on the deck as a result.
Overall, almost all name brand manufacturers of reel to reel tape decks from the 1960s to the 1990s used quality capacitors that stand the test of time. Despite having serviced 100s of Akais, Pioneers, Sansuis, and Teacs, it’s exceptionally rare that a capacitor fails. Every deck has its strengths and weaknesses, and Akais have bad transistors (see the Akai summary in a separate article here), etc. Generally speaking, the capacitors in these decks are still fine as of 2022. There’s no need to recap these decks.
Additional recapping risks
Many of the people that claim recapping is mandatory aren’t techs, and are reading articles written online by other non-techs.
After learning the hard way many times, I now use the approach: ‘solve every problem in a reel to reel before recapping’. Failure to do so can result in additional problems, which become a royal pain to track down and resolve. An example: A 45 year old Akai reel to reel comes in with ‘left channel is dead’ complaint. A person that isn’t a tech, and decides to recap the Akai before troubleshooting and solving what the actual problem is, goes in and buys 50 capacitors and recaps the deck, hoping the ‘no record’ problem will be fixed.
That person accidentally installs a capacitor backwards (electrolytics are polarity sensitive) in the right channel. Now he puts the deck together again, and finds that the right channel records, but with no bass, something that it didn’t do before. The left channel problem was actually a bad transistor, it had nothing to do with the capacitors, and now has a deck that is worse off than before. He may now take it to a tech, who has to trace down the bad transistor in the left channel, but then has to spend an additional 2 hours of bench time to trace down the fault that the client has introduced into the deck by recapping. Parts around the incorrectly replaced capacitor may also be damaged or blown now, resulting in additional bench time and parts costs.
Another thing to be aware of, is that the PC board foil traces can get brittle over time, and lift off the circuit board if a solder pad is unsoldered and resoldered without due care. Worse yet, I’ve seen a few decks come in where someone trying to repair the deck has used acid core solder, which is instant death to a PC board. Beware!
The Exceptions, where recapping is mandatory.
I post often in RTR groups online.. Revox/Studer, Tandberg and Technics decks require mandatory recapping.. after the deck has been tested for all functions before recapping.
Revox and Studer decks require a full recap, especially with the Revox A77 models, and every single Studer deck that I’ve seen through here. Revox/Studer used two brands of capacitors that are known to fail regularly, and those are the Rifa motor capacitors that are known to explode, and the Frako brand of capacitors. The exploding Rifa caps are so common now, that I automatically replace them before even powering the deck on.
The Frako brand are especially nasty, as rather than losing value over time, as most bad capacitors do, the Frakos will work fine one day, and then go to a dead short the next time you turn the deck on. This results in dead channels, or blown fuses. The Frako capacitors can also leak, however I have not yet seen them cause PC board damage as the electrolyte oozes out of the bottom of the capacitor.
As of this writing (2022), the later model Revox decks (B77 and later) can still be used without a full recapping (but the Rifa motor caps need to be changed). I do however recommend a full recap of any Revox for long term reliability.
The pro division of Revox, the Studer brand, has several models of decks (the A810 and A807) that run very hot internally, causing premature failure of capacitors. Considering that many of these decks were on 24/7 in studios and radio stations, they need a full recapping at this point. I recapped a Studer A80 24 track machine in 2020, and it took about 100 hours for the full service, and around 500 capacitors to make the deck reliable. Not a weekend job, to be sure!
Technics made a really nice series of decks, starting with the 1500 model. Even the earlier Technics decks, made under the Panasonic name (Panasonic is the parent company of Technics) were no slouches as to performance, and work well with great specs. The problem is, Technics used Panasonic capacitors throughout all of their decks (and turntables, and stereos, etc), and these caps (usually light purple, or dark blue in color) are known to leak. Worse yet, the electrolyte comes out of the bottom of the capacitors, seeps through their mounting hole, and then starts attacking the copper foil on the bottom side of the board. See below for the damaged PC board traces on a Technics 1500 series I recapped recently. When that electrolyte mixes with the solder, it discolors, and becomes almost impossible to remove. The solution is to add a jumper wire from the damaged PC board trace over to the next intact solder pad. Then clean the PC board area with isopropyl alcohol to try and get rid of as much electrolyte as possible. It works, but It’s an ugly repair.
Interestingly enough, even with a bunch of leaking capacitors in the Technics 1500 series, the decks continue to work with all functions intact. ‘My deck is in great shape, it doesn’t need recapping’ is a comment I see posted online about the Technics 1500s. No, sorry, they are a time bomb waiting to happen, as the electrolyte eats away at the PC board.
As with Revoxes ,Tandberg used lots of Frako and Rifa capacitors in their electronics, and they all need a full recapping. The problem with Tandberg is, they usually have a number of other problems that are age related within the decks, so many are write-offs. Due to the lack of available parts for them (not many were sold compared to other brand names worldwide), not a lot come through my repair shop.
The Bottom Line
Replacing anywhere between 35 and 500 capacitors in a reel to reel deck is very time consuming and expensive. If you can afford the extra money to recap a deck, then by all means do it. I always give clients the option to do a recap if they so choose. If you want to keep your deck for 10+ years, then definitely do a recap. If a reel to reel is a part of your vintage stereo, and is cool to look at, and to play the occasional tape, it may not be worth it for you to recap the deck.
Recapping a deck is like rebuilding an engine in a vintage car. You can tune up a vintage car engine, and if the block and various components are in good shape, the engine will continue to run just fine. Just like a vintage car engine, a reel to reel does not necessarily require a full recapping, and as with a car, you can rebuild the engine, but if the transmission is shot, rebuilding the engine won’t fix your problem.
I keep a running tab on reel to reel decks that I see through here for servicing. If I see a recurring failure of any part in a make or model of deck, I will make note of it, and will update this document as I see regular failures happen.