Technics dv-280 stereo system -cassette dead

Picked this up a few months back and just hauled it out. The units power up, and lights come on but the cassette deck stubbornly remains dead.

This is a 'pseudo-separates' affair, where each box is connected by means of a flat ribbon cable. The main trafo. is in the amp which then feeds a 'sound processor'/input selector box, from whence the dvd and cassette decks are fed. The dvd, which is downstream from the cassette, powers up fine. I'm assuming they use the same power rail, so will concentrate on the cassette unit first. Going to take some measurements on the cassette pcb, but I'd like the service data to speed things up, as this is quite a complex unit and it would save me the hassle of having to unscrew and open all the boxes to trace the basic voltage lines.

Anyone suggest a source for a schematic? Tried eserviceinfo to no avail.... cheers, B

Reply to
b
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Also forgot to mention: no audio through speakers, and through headphones nothing either -well, I get a low hiss (vol. at full) when in tuner mode, despite the search mode working and stations appearing as 'tuned' in the display....

-B

Reply to
b

My educated and experienced guess is a missing voltage.

Reply to
Meat Plow

I've sent you a set of schematics direct off-group. Let me know that you get them ok

Arfa

Reply to
Arfa Daily

get

Quick update. Took a few measurements - all 3 entry safety resistors in the cassette main pcb 'psu' are fine with the correct voltages present. Checked Q604, which drops the 10v to 5v and that has 5v on its emittter. This 5v is also present on pin 5 of main pcb connector 901 which goes to the LED/button panel. Checked Q602 the 9.6v regulator. Voltage present and correct there too. hmmm... could this be something amiss on the button /LED panel? Will do this next. As an aside, whilst I had the thing on, I noticed there is a sub pcb in the amp module with 3x B1548 power transistors mounted on a small heatsink - getting red hot, not a good sign. may or may not be related.

-B

Reply to
b

These units are known for bad joints on any heatsink-attached transistors.

Arfa

Reply to
Arfa Daily

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