Technics Tape Deck repair Part 1. 

I have this exact same unit, I bought it new around 1982 I think. I started to have trouble with it a few years ago, the supply reel would overspin after tape runout. It also had the speed wobble that this unit has. I took it down from my shelving and put it away for five years or so. I recently decided to embark on a journey to repair it. It's a magnificent looking machine, and I still have an extensive library of tapes. I've actually just started a complete disassembly and rebuild of the unit right now ( Feb 2022). I have removed the motors and all circuit boards, taking extensive photos along the way. I'm going through each board trying to find defective parts. So far, I have found some defective caps in the power supply board, and the microswitch that is linked to the take-up reel tensioner was defective. The microswitch is lever activated, and had a very high resistance when closed. That was tricking the torque control circuitry into misbehaving. I'm waiting for the parts I ordered to come in, but in the meantime I'm testing every cap on every board and every semiconductor. The pull on speed control switch was intermittent too, but that resolved with multiple uses of contact cleaner. This will be a very time consuming project but well worth it. I wish I know more about circuit theory though, this guys sounds quite knowledgeable. I'm strictly a hobbyist level repairman, but enjoy it.

Very Good Explanation.....I still have my Alignment Tapes for aligning Cassette Tape Decks..I use To run an Audio VCR Repair Shop from 1986 to 2002. I still get a phone call from time to time to align their Tape Decks!!! Thank You for a Great Video!!!

The 10 volt caps on the capstan control board have to be replaced. These have a TON of leaking and corroded 10 and 16v volt caps, all the electrolytics need to go. There are about 180 of them. The phase and frequency controls on the back are set with a scope, pots on the right rear, 2 pots.. Brakes need the felts replaced, with cork, they are for station keeping only. There are a few other typical Technics specific and general open reel service work that needs doing. The boards do remove,or move in their removable mount frames for easy access service and testing if you follow the service manual. It takes me 30 or more hours to restore one of these, I have an RS-1506 ON THE BENCH NOW, it'll be 30-40 hours including re-veneering the Cherry wood sides, refinish and silk screen the face, as well as custom finish knobs and buttons, Questions or any help needed feel free to contact me.

Hello, Very instructive this movie, but I am curious if you have already found the problem, because my deck has the same problem with the speed? Kind regards Rene

A lot of talking, but no solution. It is actually a simple one: the capstan motor control circuitry must be (re)adjusted according to the service manual. It is described in the RS-1500 service manual (also applicable for the RS-1506/1520/1700) in Volume 2 on page 21. The adjustment requires a scope with at least 2 channels. Adjustment is done on 2 trimmers at the backside of the deck, which are accessed through the holes in the horizontal metal bar below the capstan motor, also visible in this video.

I was thinking that it might be a tension adjustment to the supply reel section and maybe putting more tension on it would help it is just a thought love the videos you post thank you very educational and keep them coming

The capstan motor in this deck has more torque than a 1975 maytag washing machine ! As a matter of fact it's about the same size as a capstan motor in a Studer A827. Talkin about over engineering or what !

Waiting for the part two, did you made it? Regards

Hello, I wonder if you have fixed the problem already? I have the same

I have exactly the same issue with my Tehcnics Reel to Reel 1500 , finally what solution you found?

I have a RS1500 with a playback issue, it will FF & RW but will not play, this is the second time this happen. The only correlation with this problem is after moving. The first time I moved and set it back up, it had the no play back issue. I took it to an electronic repair shop and they fixed it. I was so happy for it to be fixed, I forgot to ask what the problem was. the second time right after moving it did the same thing. I am wondering if there is some sort of transport issue. any help will be appreciated.

"IF we find a solution it will be on Pt2" - Guess they never found a Service Man to figure out the problem.

I have the same issue with my RS1506 plus a problem with the head block switch which is a bit loose and intermittent.

i can't find part 2 ..did you get it fixed,because i have the same problem.regards Nick

So in the end, the simple and best way, is to leave it as it is, and let it run on manual instead of automatic speed control.

I have the formal schematics for the 1500 series machines from their (Technics) service manuals. They appear to be similar to what you already have except they are, if I recall 20 x 14" and include further annotations of scope waveforms and what you should expect to see at various test points. Over 30 points in all. Very helpful for diagnosing problems like this. PM me if you are interested. I might be able to scan this schematic for you

I have the same issue with the technics US 1506

counter chip failure?

The first thing i would do is Clean and Lubricate all rolling wheels. Next thing is to place a reel and play it, then watch how the tape rolls around the wheels you lubricated see if there a change. ..... .... OK ..... ... The next thing for me to say the Reel to Reel needs to be calibrated somebody might of played with that inside of the back of the Reel to Reel. A pro should do this.>>>>>ADJ>>>>

Reverse your line cord

Where is part two, can you fix it or just talk......

Are you interested to repair tascam 52 thx.

Look at this; m.ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-LK8dTAvpohc.html .... seems like the quartz speed is controlled by a sensor in the capstan motor. The guy on the video talks about that at the end of the video.

replace all electrolits and you are fine all purple one are going to short