I need to find a replacement. My friend found an HK 2000 tape machine, and he records on tape.
The machine's output sounds like it has no signal, but amplification is happening (annoying loud noise, and volt meters redline).
Inside I found that there are 2 C1344 transistors per amplification from the heads before any equaliziation etc. They also don't measure right, appearing to have gone bad. I've only found one post anywhere mentioning they are weak in the chain. Trouble is I can't find any idea of what to replace them with.
The machine's output sounds like it has no signal, but amplification is happening (annoying loud noise, and volt meters redline).
Inside I found that there are 2 C1344 transistors per amplification from the heads before any equaliziation etc. They also don't measure right, appearing to have gone bad. I've only found one post anywhere mentioning they are weak in the chain. Trouble is I can't find any idea of what to replace them with.
Nice little transistors!
Here is the data sheet on them.
2SC1344 pdf, 2SC1344 description, 2SC1344 datasheets, 2SC1344 view ::: ALLDATASHEET :::
Almost any low noise NPN transistor should be OK. Just watch the lead orientation!
Here is the data sheet on them.
2SC1344 pdf, 2SC1344 description, 2SC1344 datasheets, 2SC1344 view ::: ALLDATASHEET :::
Almost any low noise NPN transistor should be OK. Just watch the lead orientation!
That symptom sounds like the multiway record/playback switches need cleaning. A classic fault 🙂
The "play" switch seems to work fine. I'll double check it. The record switch is a bit different. I'll take a closer look at what is going on with it. If I remember right it moves a thing that switches like 10 leads at a time.
But again, the transistors don't test like they should. I've got a bunch of 2sk170's, so I suppose that'll work. I thought the behavior was basically like having an open for the signal.
But again, the transistors don't test like they should. I've got a bunch of 2sk170's, so I suppose that'll work. I thought the behavior was basically like having an open for the signal.
The "thing with ten leads" sounds more like the classic record/play switch, see post #17 here,
http://www.diyaudio.com/forums/analogue-source/195121-pioneer-ctf9191.html#post2690338
2SK transistors are FET's, 2SC devices are silicon npn.
http://www.diyaudio.com/forums/analogue-source/195121-pioneer-ctf9191.html#post2690338
2SK transistors are FET's, 2SC devices are silicon npn.
Oh boy, duh... I should probably not dig in until I wake up.
Yes that is the switch. I'll check but I don't think it engages for playback, but another switch does.
How do you recommend cleaning?
The problem happened overnight, or literally one day just started, rather.
The switch will move when record is selected. I'd still say give it a squirt with WD40 as outlined in the other thread. Move the switch to and fro rapidly by hand to clean it.
Yes but the problem is there isn't any playback (and this switch doesn't appear to opperate for playback). Volt meters hit the top, and nothing comes out. Can this be caused by dirty connections in it? I suppose that'd make sense during "play" operation, considered that the other switch for "play" that lets the signal to the output, appears to be fine.
The record/playback switch is that long multileg thing. It switches the amplifier circuits from the record to playback modes. That has nothing to do with the transport control switches on the front panel. The R/P switch is activated by the mechanism. The PLAY button you can press on the front is a transport control, and has nothing to do with the audio path. The way you have said in various ways that playback is not involved or whatever leads me to think you may be confused on that.
The audio always runs through the R/P switch, the switch is always involved. It may stay in its rest position during playback, and only move to record for recording, but both of those are positions, and if it gets dirty, then the amplifier functions cannot occur. It is still involved, even if it doesn;t move.
As Mooly pointed out in post #3, that is a VERY common point of trouble in tape decks.
The audio always runs through the R/P switch, the switch is always involved. It may stay in its rest position during playback, and only move to record for recording, but both of those are positions, and if it gets dirty, then the amplifier functions cannot occur. It is still involved, even if it doesn;t move.
As Mooly pointed out in post #3, that is a VERY common point of trouble in tape decks.
Relax. I understand it.
The play button triggers a switch that either does or does not let the audiopath go to the volume slides and back out to the RCA jacks, btw. (but it appears to be fine, could be a culprit however, but not now)
WD40 has been done, testing will commence in a day or so.
The play button triggers a switch that either does or does not let the audiopath go to the volume slides and back out to the RCA jacks, btw. (but it appears to be fine, could be a culprit however, but not now)
WD40 has been done, testing will commence in a day or so.
Often these things have only one amplifier per channel. The signal is amplified from the input to the heads for Recording and feeds the signal from the heads to the outputs for Playback.
The switch often, not only changes the direction of the signal flow to/from the heads but it also changes various settings within the amplifier itself.
The switch often, not only changes the direction of the signal flow to/from the heads but it also changes various settings within the amplifier itself.
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