I scored some rough Fisher tube equipment a week ago and will begin the journey of restoring them. What I scored was a Fisher 500B receiver, a KM-60 Tuner, and a KX-100 Amp. None of them have cabinets and only the 500B has tubes. For this thread, first up is the KX-100 amp.
The unit looks generally complete excepting for the missing tubes. It is very dirty and the chassis seems to have some pitting/oxidation, the trannies have some rust, and at least one cap (C1?) from the power supply has broken off due to corrosion. I'm going to restore it, but will need some guidance as to what "must" be replaced vs. what simply needs to be checked and cleaned.
I've found an assembly manual for the KX-100 and two versions of the Service Manual for the almost identical X-100-B. The Service Manuals have good diagrams for the X-100-B which I understand have a different (adjustable) bias circuit. I've got a multimeter (RLC and V) and a USB oscilloscope. I intend on getting a variac before powering it up but that's down the road a bit. I'll be using deoxit on the controls as part of the cleaning. I haven't worked on tube equipment since the 1970's, so I've forgotten most of what I knew - still I have a healthy respect for the voltages involved and I understand electronics from a hobbyist perspective and electrical theory from a professional perspective. I am not an expert and I'm humbly asking for guidance.
I have done no verification of anything on the unit excepting for a brief visual inspection. So where do I start? Should I undertake the cleaning of the Fisher Tube chassis based on the sticky in this Fisher area first? Would anyone recommend which parts I should replace right off such as the electrolytic caps? There seems to be C1, C2, C3 and C4 that are the only electrolytics some of which are combo caps. Not too many to deal with if that is the recommendation. I see there are mylar coupling caps on the diagram. If these are not damaged is there any reason to replace them out of hand? There is a KX-100 restoration thread I've read through that is very good, but it included a lot of mods mentioned and only some of it was diagrammed.Further down the road, I'd be interested to hear if those mods are strongly recommended or just an optional upgrade.
Here are some pics to get started. I'll post some better closeups soon.
The unit looks generally complete excepting for the missing tubes. It is very dirty and the chassis seems to have some pitting/oxidation, the trannies have some rust, and at least one cap (C1?) from the power supply has broken off due to corrosion. I'm going to restore it, but will need some guidance as to what "must" be replaced vs. what simply needs to be checked and cleaned.
I've found an assembly manual for the KX-100 and two versions of the Service Manual for the almost identical X-100-B. The Service Manuals have good diagrams for the X-100-B which I understand have a different (adjustable) bias circuit. I've got a multimeter (RLC and V) and a USB oscilloscope. I intend on getting a variac before powering it up but that's down the road a bit. I'll be using deoxit on the controls as part of the cleaning. I haven't worked on tube equipment since the 1970's, so I've forgotten most of what I knew - still I have a healthy respect for the voltages involved and I understand electronics from a hobbyist perspective and electrical theory from a professional perspective. I am not an expert and I'm humbly asking for guidance.
I have done no verification of anything on the unit excepting for a brief visual inspection. So where do I start? Should I undertake the cleaning of the Fisher Tube chassis based on the sticky in this Fisher area first? Would anyone recommend which parts I should replace right off such as the electrolytic caps? There seems to be C1, C2, C3 and C4 that are the only electrolytics some of which are combo caps. Not too many to deal with if that is the recommendation. I see there are mylar coupling caps on the diagram. If these are not damaged is there any reason to replace them out of hand? There is a KX-100 restoration thread I've read through that is very good, but it included a lot of mods mentioned and only some of it was diagrammed.Further down the road, I'd be interested to hear if those mods are strongly recommended or just an optional upgrade.
Here are some pics to get started. I'll post some better closeups soon.
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