I had a problem with the noisy transformer at TR2055. After 1h playing it started 'buzz' like a hell, so the new audio toroidal transformer ( it has the traditional one ) has been designed. It looks and works perfect now. If you have the same problem let me know.

I see one on the forum.

I see them on ebay.

I know some guy I ever sold to AND bought from having one.

I have the impression, they are not so scarce.

I have read, they were an anniversary item, or a dealer showpiece.

Does anybody know about figures and percentages of the TR2075 (and apparently, also TR2055?) ?

And the reason, they were built?

My own one in the meantime plays well, but it needs some more testing, and also some kind of polishingof the front knobs (guess I use a drill, soft cloth, and polishing paste?).

Find my showoff page here!http://www.gerardslikker.nl/tandberg-tr2075-acrylaat.htm

Br Gunnar 

From what I could see there are 2 problems both in the power amp stage. Sometimes the DC voltage on the speaker outputs of both channels with no input signal is relatively ok and stable at around 20 mV but sometime one channel would be at around -200 mV with occasional few hundred mV jumps. This makes sometimes the output relay disconnect. Mostly after warming up this DC offset is gone and both channels would be working ok if it wasn't for the fact that maximum peak to peak voltage before clipping is around 9V which is too low as rails are +/- 40V. That is the second problem.

I think both problems are related to voltage amplification stage. I'll attach a part of the schematic. When there is a DC offset I can measure on Q703(BD420) that it conducts in both directions between base and collector but I am not sure if it is because that transistor is shot or because of Q707(MPSA13). I don't really like how Q707 is mounted, its legs are loosely in connector where connection could be problematic and transistor is stuck between output transistor bracket and heat sink. I cleaned the connections but that didn't help.

I can of course remove both transistors and measure them to check but as the problem is intermittent I plan on replacing them both in both channels. While MPSA13 is cheaply available at Reichelt, that is not the case for BD420 . Do you know a modern replacement for BD420?

I believe other TR series models use similar old Motorola transistors so somebody could be familiar with replacements.

When both channels are working good and I input 1kHz sine wave, the output looks quite ok with no distortion and amplitude increase with volume increase but the maximum amplitude of only 9V before clipping. What could be reason for so low voltage before clipping? Maybe I should mention that I use 8 Ohm resistors as dummy load.

Ola S.

I tried to search on the net, but only found most common 12v versions etc.

There's a total of 6 pcs inside a TR 2025 for illuminating the scale screen.

Also, if there is suitable led substitute available, it might be ok too but brightness have to be equal to original, I don't want it to be much brighter.

Any help with this?

Cheers,

-Sami

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It was always one of the main problems during the TR20xx restoring process - what to do with the scratchy or damp housing ?  So I decided to make the new one. The carpenter project started and I made a wooden covers for the TR20xx series. It's made from a high quality walnut veneer ( all series ) or painted black ( only fits TR2025/30/40/45/60 ). It's a plug and play spare part. As a part of project you will get the proper labels as well ;). If you need one let me know.