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Fostex X-15 Help

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Fostex X-15 Help

Postby forumuser845268 » Sat Oct 10, 2020 2:10 pm

Hello all,

On a whim I bought 2 Fostex X-15 4 track cassette recorders which were described as broken in different ways. I've been tinkering with them and found that one of them has a snapped oscillator PCB so is going to be a parts doner, and the other works well apart from no playback on track 3. It definitely records onto track 3 as when I flip the tape there is sound coming from track 2...

The machine with the broken PCB plays back on all 4 tracks, but only records onto 1+3.

This is beginning to sound like a riddle, apologies.

What I want to do is locate the issue on the machine with no playback on track 3, and replace the dodgy part/s with part/s from the doner machine.

The thing is I don't really know where to start with testing. I'm fairly new to this sort of tinkering but I'm good with a soldering iron and can use a multimeter so I think I can do this! I'm hoping someone might be aware of a common fault with these machines that I can try and find, or at least have some idea of where I should start looking and how to test the various parts of the circuit?

One thing to note that seems important is that there has clearly been a lot of heat around the top of the machine around channel 3 as there is a bit of melting going on! I'm guessing that is the cause of the lack of playback, but maybe someone would know more specifically which components would generate that much heat and why.

All and any help gratefully received!
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Re: Fostex X-15 Help

Postby Tim Gillett » Sat Oct 10, 2020 3:33 pm

As I recall the PCBs in the X15s had fairly large printed tracks so seeing and even repairing the cracked PCB and tracks may not be too difficult. Re the track 3 no playback a common problem with many 2 head tape machines not used for a while is dirty switch contacts in the record /play switch. Just exercising it back and forth ten times or so might bring back the playback or at least enough to tell if the switch needs a proper clean. HTH.
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Re: Fostex X-15 Help

Postby shufflebeat » Sat Oct 10, 2020 10:37 pm

There is a slim to middling chance I have an x-26 lying round somewhere if that's of any interest.

(UK based).
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Re: Fostex X-15 Help

Postby forumuser845268 » Mon Oct 12, 2020 8:20 am

Tim Gillett wrote:As I recall the PCBs in the X15s had fairly large printed tracks so seeing and even repairing the cracked PCB and tracks may not be too difficult. Re the track 3 no playback a common problem with many 2 head tape machines not used for a while is dirty switch contacts in the record /play switch. Just exercising it back and forth ten times or so might bring back the playback or at least enough to tell if the switch needs a proper clean. HTH.

Thanks Tim, I've had a good old wiggle of all the moving parts and cleaned out a load of crud but haven't managed to get even a crackle out of channel 3 sadly. I traced the signal path of channel 3 and had a visual inspection of all the components, but nothing looks obviously knackered. I guess the best next step is to remove components in turn and replace with components from a working channel on the doner machine and test as I go?
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Re: Fostex X-15 Help

Postby forumuser845268 » Mon Oct 12, 2020 8:22 am

shufflebeat wrote:There is a slim to middling chance I have an x-26 lying round somewhere if that's of any interest.

(UK based).

Hey shufflebeat, I could be interested! How much would you be looking for if you do indeed have it lying around?
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