Hi everyone.
I'm about to start restoring an old TEAC A 105 tape deck, from the late 70s, that belonged to my family and it hasn't been used for more than 25 years.
I have made several restoration and maintenance jobs of different audio items, but it's my first time around a tape deck. This deck is not something that it's considered really worthy but I would like to fix it for old's time sake.
I remember during it's final days of use back in the early 90s, it had a problem on one of the channels and after a while, only one was working. So I thought it would be quite an easy fix.
But yesterday when I powered it up, both channel meters (needles) were bouncing at the very end rapidly (absolute peak).
Of course I didn't connect it with any amp since I am scared of causing any damage to any other equipment
I found the service manual online here :
TEAC A103 A105 A106 A107 Service Manual download, schematics, eeprom, repair info for electronics experts
but I don't know where to start from. The PCBs disassembly for this one seem also quite a hard task.
.I have a signal generator and an oscilloscope and pretty good soldering - desoldering skills.
Some easy guesses are replacing the bigger electrolytic filter for a good start , or trying to fix, clean or replace the calibration pot (or pots) for the meter levels etc.
I have no other idea where to start from as I said before and I just may be totally wrong with my guesses, so before I do anything I seek more experienced people's advice.
Thanks in advance
I'm about to start restoring an old TEAC A 105 tape deck, from the late 70s, that belonged to my family and it hasn't been used for more than 25 years.
I have made several restoration and maintenance jobs of different audio items, but it's my first time around a tape deck. This deck is not something that it's considered really worthy but I would like to fix it for old's time sake.
I remember during it's final days of use back in the early 90s, it had a problem on one of the channels and after a while, only one was working. So I thought it would be quite an easy fix.
But yesterday when I powered it up, both channel meters (needles) were bouncing at the very end rapidly (absolute peak).
Of course I didn't connect it with any amp since I am scared of causing any damage to any other equipment
I found the service manual online here :
TEAC A103 A105 A106 A107 Service Manual download, schematics, eeprom, repair info for electronics experts
but I don't know where to start from. The PCBs disassembly for this one seem also quite a hard task.
.I have a signal generator and an oscilloscope and pretty good soldering - desoldering skills.
Some easy guesses are replacing the bigger electrolytic filter for a good start , or trying to fix, clean or replace the calibration pot (or pots) for the meter levels etc.
I have no other idea where to start from as I said before and I just may be totally wrong with my guesses, so before I do anything I seek more experienced people's advice.
Thanks in advance
Interesting would be to hear what it is actually outputting, since You have pegged VU's.
Is there a headphone output ?
Start by cleaning switches & pots. Don't touch PCB calibration pots at this time.
Inspect belts, clean heads & pinch roller. If the head is oxidized try to polish it first.
No sandpaper or scotch brite please. Plain cloth & finger pressure. Ok a drop of Brasso perhaps.
Check if there is a safe Voltage at the output (say 0 to 2V), connect it to an amp & slowly raise the volume.
Check both stopped & after pressing play, since when You press Play PB circuits are powered / unmuted, before connecting to an amp. Make sure experimental tape is inside. Don't try Your rare tape collection at this time, since it can be damaged.
What do You hear ? Hum, Noise, Distorted music, Nada ?
It can give You a clue where the fault is.
One time my old Pioneer was outputting a high squeal on one of the channels and it was a dirty 40 pin ? mechanical Play / Rec switch (feedback perhaps).
Is there a headphone output ?
Start by cleaning switches & pots. Don't touch PCB calibration pots at this time.
Inspect belts, clean heads & pinch roller. If the head is oxidized try to polish it first.
No sandpaper or scotch brite please. Plain cloth & finger pressure. Ok a drop of Brasso perhaps.
Check if there is a safe Voltage at the output (say 0 to 2V), connect it to an amp & slowly raise the volume.
Check both stopped & after pressing play, since when You press Play PB circuits are powered / unmuted, before connecting to an amp. Make sure experimental tape is inside. Don't try Your rare tape collection at this time, since it can be damaged.
What do You hear ? Hum, Noise, Distorted music, Nada ?
It can give You a clue where the fault is.
One time my old Pioneer was outputting a high squeal on one of the channels and it was a dirty 40 pin ? mechanical Play / Rec switch (feedback perhaps).
Try posting with the gang over at tapeheads.com:
Cassette - Tapeheads Tape, Audio and Music Forums
Lots o' cassette experts there.
Cassette - Tapeheads Tape, Audio and Music Forums
Lots o' cassette experts there.
First results. Following MAAC0 advice I cleaned up the pots and the switches, rolled them left right several times and they stopped pinching after a short while. Voltage on outs good as expected, so I decided to test with a quite new tape.
Immediately I noticed really bad and slow movement of the tape (the music was coming several pitches down and detuned) and no way of going the tape forward or backwards. So I guess the problem now is around the base pullies and their controls and the next step is either cleaning them or replacing belts or other parts etc.
Any new ideas or advice please?
Immediately I noticed really bad and slow movement of the tape (the music was coming several pitches down and detuned) and no way of going the tape forward or backwards. So I guess the problem now is around the base pullies and their controls and the next step is either cleaning them or replacing belts or other parts etc.
Any new ideas or advice please?
News. Quite bad news. While cleaning the capstan and the roller, there was a small explosion and smoke coming from the mechanism small board. I guess a capacitor exploded. Even if it powers up and seem working.
So now it's time to change all the electrolytics (I will replace the large power filter ones). And the hard part is disassemble the thing in order to reach the pcbs.
I attach some pictures of the mechanism and the level meter pinching. Now it peaks only on the left channel.
What do you think?
So now it's time to change all the electrolytics (I will replace the large power filter ones). And the hard part is disassemble the thing in order to reach the pcbs.
I attach some pictures of the mechanism and the level meter pinching. Now it peaks only on the left channel.
What do you think?
Attachments
That pinch roller needs a good scrubbing with isopropyl alcohol. Probably the heads too.
I HATE it when the magic smoke that makes electronics work escapes!! Sometimes it's really hard to get it back in!!!
I HATE it when the magic smoke that makes electronics work escapes!! Sometimes it's really hard to get it back in!!!