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The HiFi chat, build and modification thread!
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Jeez, this 34 is fighting me all the way!
Sorted the input switching out (logic chip fried).
Testing the audio path tonight - no output both channels. :facepalm: Traced it to the tape monitor logic gate, its also fried because if I short the signal path through it, signal gets as far as the output mute circuit ... where it stops :facepalm: Output mute circuit is not switching out of mute even when the PSU is stable... I suspect a leaky transistor after the comparator. I'll sort the tape monitor logic out first (parts on order) and then think about the mute circuit!
Still, at least it should be ready for the hifi selling season!!
Decided to sell on the FM4 as 'spares only'. In technical terms, it's whats known as f*cked. When I started investigating it, the battery leak has dissolved most of the tracks within a few inches of it, including the tracks near the processor. Shame. I always wanted an FM4...
Sorted the input switching out (logic chip fried).
Testing the audio path tonight - no output both channels. :facepalm: Traced it to the tape monitor logic gate, its also fried because if I short the signal path through it, signal gets as far as the output mute circuit ... where it stops :facepalm: Output mute circuit is not switching out of mute even when the PSU is stable... I suspect a leaky transistor after the comparator. I'll sort the tape monitor logic out first (parts on order) and then think about the mute circuit! Still, at least it should be ready for the hifi selling season!!
Decided to sell on the FM4 as 'spares only'. In technical terms, it's whats known as f*cked. When I started investigating it, the battery leak has dissolved most of the tracks within a few inches of it, including the tracks near the processor. Shame. I always wanted an FM4...
Rod_Saetan
Old School Grand Master
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I have this Garrard SP 25 MKIV with a Shure head that is surplus to requirements, it is working but not in 'auto' which seems to be a common fault.
I'd ideally like to swap for a 'vintage-ish' Amp that I can run a turntable and ipod through - anyone got ought?
I'd ideally like to swap for a 'vintage-ish' Amp that I can run a turntable and ipod through - anyone got ought?
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Still thinking what I should do with this one. No idea what's wrong with it, but I'm certain it won't be easy to fix.
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Rod_Saetan":3hvugel6 said:I have this Garrard SP 25 MKIV with a Shure head that is surplus to requirements, it is working but not in 'auto' which seems to be a common fault.
I'd ideally like to swap for a 'vintage-ish' Amp that I can run a turntable and ipod through - anyone got ought?
I have a few amps available - Garrard is ebay fodder I'm afraid.
Raging_Bulls":3mdmawzm said:Still thinking what I should do with this one. No idea what's wrong with it, but I'm certain it won't be easy to fix.
You might be surprised - it's all discrete components so somebody with a bit of love and an oscilloscope should be able to help. Is it valve or transistor?
Finally complete!
That was 'challenging'. Replaced pretty much every IC involved with the switching logic, several bits of the mute circuit, two LED driver transistors, and all the electrolytics - before I even thought about upgrades! The paint's not to everyone's taste but I like it
That was 'challenging'. Replaced pretty much every IC involved with the switching logic, several bits of the mute circuit, two LED driver transistors, and all the electrolytics - before I even thought about upgrades! The paint's not to everyone's taste but I like it
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