My Luxman K-1 has developed an annoying fault, it still plays fine, at normal levels, but it isn't picking up the line level input signal properly. I thought it wasn't even registering the fact there was any input until I tried cranking the rec level dials all the way up, and then the VU meters started moving. so something has gone wrong with the electronics, anyone got any idea how to start trying to diagnose the problem?
Better start here:
Cassette - Tapeheads Tape, Audio and Music Forums
It might be that you have a switch on the front panel that allows you to monitor the tape or the line input.
I can't source the schematic manual from my own country as hifiengine blocked all the internet networks from Romania...You can send it to me on email though at gopofirst@yahoo.com if you have the time.
Cassette - Tapeheads Tape, Audio and Music Forums
It might be that you have a switch on the front panel that allows you to monitor the tape or the line input.
I can't source the schematic manual from my own country as hifiengine blocked all the internet networks from Romania...You can send it to me on email though at gopofirst@yahoo.com if you have the time.
The electronics (generally across all makes and models) are pretty reliable and so I would begin by looking for something simple. Assuming its all connected correctly and the input switches are set appropriately then the first suspect on any old cassette deck is the multi way slide switch/s that change the deck electronics over from play to record mode. There are typically two of these and they are around 3 to 4 inches long and an eighth inch wide with perhaps 30 or more pins on them. These often go faulty/intermitent and often respond to cleaning.
Your fault should be a doddle with a service manual to check supplies and so on.
Your fault should be a doddle with a service manual to check supplies and so on.
I think Mooly has probably figured it out, or I hope so, as that sounds a simple fix. Here's a picture of my unit, as you can see, there are no front panel switches to set wrong, I recorded a tape last night and it was fine, but this morning, not working. I'll take the top of and take some pics, then hopefully cleaning those big input switches will do the trick, I have some WD40 handy.
I have the service manual, if I interpret it right, there are two of those switches on the master board, labelled S101.
I have the service manual, if I interpret it right, there are two of those switches on the master board, labelled S101.
Attachments
Those are the ones. Initially just give them both a good whizz to and fro by hand and see if it has any effect. Beware that doing that while playing WILL almost certainly switch the unit to record and erase what is on the tape.
Its also worth checking the power supplies to the line input stage and also looking at how the mic input is switched. It might be automatic on this model and rely on the presence of the jack plug being fitted. These are all mechanical switch problems waiting to happen.
Its also worth checking the power supplies to the line input stage and also looking at how the mic input is switched. It might be automatic on this model and rely on the presence of the jack plug being fitted. These are all mechanical switch problems waiting to happen.
Cheers. I shall tape the top off and hopefully will be able to access them easily. I shall report back shortly.
Given the fact that they both worked a day before i doubt that both are done now...They should be both on or off at the same time ...
OK, good luck 
Also don't discount an input problem. Are you sure there is audio arriving at the socket from whatever you have it connected to?
Also don't discount an input problem. Are you sure there is audio arriving at the socket from whatever you have it connected to?
Yes, definitely audio going in, if I turn the rec levels knobs all the way up, then the vu meters move, so it is getting a signal.
there must be a mechanical system acting those switches at the same time...try them by hand.They should be moved by the REC button.
AAARRRRGHHH!!! DO NOT use WD-40!! It is a dirt magnet!! Use Caig DeOxit, the best contact cleaner available.
Well I've finally managed to get the screws out and remove the bottom of the case to access the PCB. The switches are easily accessible. I've ordered a can of switch cleaner, will give them a good dose when it arrives and report back.
If it both LH & RH channel affected that shows it is a fault that affects both channels - eliminates any fault that affects one channel only.
Note that if a source is disconnected, the (very) low level signal may be just "leakage".
Check you have a proper signal on the source cable by eg plugging into an amp input.
Or try the tape with another known good source.
Always eliminate the simple/stupidly obvious first before going deeper.
Note that if a source is disconnected, the (very) low level signal may be just "leakage".
Check you have a proper signal on the source cable by eg plugging into an amp input.
Or try the tape with another known good source.
Always eliminate the simple/stupidly obvious first before going deeper.
Already tried 3 sources, same issue with all of them, so it's definitely the tape deck itself that has a problem.
Finally got around to cleaning the switches - flooding them with switch cleaner than moving them back and forth a lot, did the two rec level pots at the same time as they could be crackly. This fixed the problem and the deck is working great again. I've made 25 recordings with it since cleaning and they all sound great.
The K-1 may have been Luxman's entry level unit, but it really isa great sounding device, both for recording and playback, seems to me it has excellent circuitry, better than many preamps I have heard.
The K-1 may have been Luxman's entry level unit, but it really isa great sounding device, both for recording and playback, seems to me it has excellent circuitry, better than many preamps I have heard.
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