Tascam 244

[theredhouseinn]

Hi folks.
I have a 244 on the bench for repair. A friend bought this in a boot sale complete with cobwebs, dust, and dead ladybirds inside.
The belt's etc had dissolved into the usual black gung.
I replaced the belts, tyres, and pinch roller tyre, 5v reg. in the power supply and the mech is now working.
The pots and switches are very noisy and intermittent. Starting with taking the tape cue board out to clean those pots I decided to do a check on the electrolytic's.
All the 22uf caps 10 off were faulty. Resistance on the Avo, anything from 10k to 100k. Capacitance on the TF2700 from 0.5uf to 7uf. ESR around 15ohms, Vloss around 20%.
The 10uf's on the board were ok. I only checked 2 of them so I assumed that the other 8 were ok.
I have made sample electrolytic checks on other Tascam and TEAC vintage recorders in the past, but never had this amount of failure.
Have any of you had this problem with a 244?
John.

[DMcMahon]

No experience of the Portastudios.

Based upon the high failure rate for the 22uF, I would not assume the rest of the 10uF are good.

David

[TIMTAPE]

Are there any audio or operational symptoms consistent with cap deterioration in the 244?

[theredhouseinn]

Hi Tim.
I haven't done any level or frequency checks yet.
I have got to finish cleaning pot's and switches.
The button ops on the mech are a bit slow to work, so poss. prob. with logic board.
I am doing all preliminary checks before I start on p.b. test tapes and recording test tones.
I just thought that I would try the forum to see if anyone has had one in such bad condition.
John

[TIMTAPE]

Sure. I have a 244 myself and havent had issues with it so far but wouldnt be surprised if at least some of the electro caps are below par. Thanks for the info on the 22uF's.

[theredhouseinn]

Checked the rest of the 10uf on the tape cue board, all ok. Replaced panel.
Removed the DBX board, 8 x 22uf on this board, all dud same as the tape cue board.
Checked the 10uf on this board, all ok, 4 x 47uf all ok.
Conclusion is that the 22uf caps were dud in manufacture.
I can see more 22uf on the i/p amp board.
I will keep you updated.

John.
pp. Tim, have your deck buttons broken off the plastic moulding yet.

[TIMTAPE]

I've seen the function buttons broken on other examples, probably from users pressing too hard when the tactile switches had become faulty.

[theredhouseinn]

Taken out the first input amp board, checked the 4 22uf's and all 4 are faulty same as the others.
I have now run out of 22uf's in my stock, more on order.
I will now run through the rest of the boards on the unit testing the 22uf's but I am sure that they will all test faulty.
John.

[theredhouseinn]

Still working on this 244.
I have now changed 52 x 22uf caps. All faulty. Anything from 0.5uf to 17uf. varying resistances.
I have taken one apart and the paper insulation between the aluminium foil has deteriorated and dissolved into a brown mush. The resistance between the pins with the foil removed is 1m ohm across the rubber insulator. The aluminium foil is a light blue colour, varying in hue. Squeezing the foils together with the paper between, the res. is anything from a few ohms to several k ohms.
Samples of other caps on all boards have tested ok. This problem appears to affect only the 22uf caps.
7 out of the 8 tactile switches are very intermittent only making after several presses, some showing several ohms resistance.
This is the worst example of a Tascam unit I have ever come across.
One day I may be able to record something on it.
John.

[williamsunique]

Maybe someone connected it up with the polarity reversed and left it connected.

Paul.