Fisher X-202 Rebuild

[2dbit]

So, the cap restuff didn't exactly go as planned. I had hoped to use a high wattage iron to get solder to flow and seal the cap back shut. No good, the case sinks just too well! I didn't want to risk damaging the caps inside with excessive heat, so I went with the rolled edge option. I have perfect bond between surfaces, so i'm going to accept it as is. I may still do a jumper to ground just to ensure good continuity over time.

Ultimately the goal was met, and that is from outside the amplifier, the restuff would be impossible to tell. Once you're in the amp you'll be able to see that the cap has been redone, but really, if you look anywhere inside the amp, restoration will be obvious.

 

[bhamham]

Fantastic job restuffing those caps :thmbsp:

What's the white stuff on the inside on the phenolic? I guess that's a glob of silicone at the top of the can? Very clean cuts - did you use a pipe cutter? Very impressive!

 

[the_nines]

While I wait for parts, I worked on aesthetics. There's a lot of work that needs to be done, but this is not a race, so I don't mind taking some time to just work on beauty and protection.

Before and after of the faceplate. The difference in the picture isn't substantial, but in person I looks a lot better, and with a nice coat of wax, it should protect against any further oxidation.

Great work on the rebuild so far, it looks great. I envy people who have the knowledge to do their own electrical work. I had my 500B and 500C rebuilt by a friend, and am waiting for my X-202-B to be finished. I should get it back hopefully this week sometime.

By the way, your faceplate looks amazing. How did you clean it? I want to clean the faceplate of my X-202-B when I get it back. I haven't cleaned it yet because I am afraid to damage the lettering.

Great job! :thmbsp:

 

[nj pheonix]

Was that a kit (the replacement parts ) or ordered individually?

 

[Ken Boyd]

Fantastic job restuffing those caps :thmbsp:

I thought the same thing.

 

[2dbit]

Fantastic job restuffing those caps :thmbsp:

What's the white stuff on the inside on the phenolic? I guess that's a glob of silicone at the top of the can? Very clean cuts - did you use a pipe cutter? Very impressive!

The white stuff is a 2 part epoxy adhesive, It's pretty amazing stuff, and should hold the tabs in place quite well!

The cuts were made after I threw in the towel on trying to carefully pry up the crimp. I spent about as much time as anyone should spend with a tiny screwdriver picking at it. The cuts themselves are actually not cuts at all. I placed the caps on a bench top sanding wheel and slowly ground down the crimp until gone. Then, just pulled the ring out.

 

[2dbit]

Great work on the rebuild so far, it looks great. I envy people who have the knowledge to do their own electrical work. I had my 500B and 500C rebuilt by a friend, and am waiting for my X-202-B to be finished. I should get it back hopefully this week sometime.

By the way, your faceplate looks amazing. How did you clean it? I want to clean the faceplate of my X-202-B when I get it back. I haven't cleaned it yet because I am afraid to damage the lettering.

Great job! :thmbsp:

One of the single best purchase anyone can make when trying to do electrical work is a quality soldering station. For years I only used a 40watt soldering iron. My solders came out solid, but switching to an iron that had an adjustable temperature with a high quality tip made soldering much more enjoyable.

As for polishing the faceplate, I used the same cleaning wax that I used on the chassis, It's Klasse All-In-One automotive wax. The stuff is amazing and did not take down the silk screening at all. Your mileage may vary, but for my project, it had no ill effects!

 

[2dbit]

Was that a kit (the replacement parts ) or ordered individually?

All parts were painstakingly ordered separately. I did this to have as much control as possible, I did a lot of research, got a lot of input from community members, and in the end feel that I've made the right choices.

Of course, in the end, everything is subjective, but I went the route of mostly orange drops, low esr/audio grade electrolytics, carbon comps for plate resistors, and 1% / 5% metal film for all other that aren't wirewounds. As for wirewounds, all wattages were raised, especially wherever heat damage was found or cracking.

 

[walyfd]

I was able to pry the cans apart using a pair of long needle nosed pliers. The first one didn't go so well, but by the third can, I had the procedure pretty well perfected.

I recrimped the cans with channel locks, but didn't use any sealant in case I had to open them up again if I made a mistake.

Beautiful work!

 

[nj pheonix]

Looks great!

 

[2dbit]

A few of the wirewounds that got replaced.

R80 and 81 are 7 watt 250 ohm resistors, they're being replaced by 10 watt versions, and are spaced from each other and the chassis by a little more to aid in cooling and to prevent cracking.

 

[2dbit]

R90 and 109 as well as R95 and R110 also got replaced/upgraded due to cracking.

Getting the 10watters in there was a bit of a squeeze, but they fit!

I did my best to maintain clearance between the resistors and the OPTs, as well as the OPT fasteners...

 

[bhamham]

Looking good :thmbsp:

Those tags on the resistors & caps e.g., R90, R109... are they edited/labeled on the pics? Very cool!

 

[2dbit]

Since the time I have to allocate to this project is typically 2 hours or less each day (many days no hours) I printed out labels as I traced the circuit from the schematic. It helps keep everything organized, and facilitates marking the schematic with what has been done as each component comes out and is replaced.

Teeenie Tiny Labels...

I'm debating putting labels on the new components as they go in, so if I need to dive in at any time, I won't have to ring out the circuit as much...

 

[larryderouin]

Watch those labels on the resistors tho. Put them on the chassis next to them so they won't burn up.

 

[2dbit]

I don't think I'd be labeling the new components, but if I did, according to the manufacturer, "When tested, tapes began to decompose only once the temperature reached 365°C. " found that to be somewhat impressive...

Oh, and have a dielectric strength of 8kv.... Total loss at 11kv... If I somehow develop that level of potential in this amp, things are going horribly, horribly wrong. Labels would likely be the least of my concerns!!!

 

[HiFiHarv]

That re stuffing is alot of work. Very commendable on your part, nice job! As you said, once inside the chassis it will be obvious that there was a restoration (so what!) I think we can be a bit more flexible inside there. Really enjoying your posts, thanks.

 

[dcgillespie]

2d -- Super job on your rebuild -- and I get to see what mine originally looked like to begin with!

Dave

 

[2dbit]

Thanks again for all the props. It's been a slow process, but it's a process that should not be rushed!

I haven't posted in a little while, since it's not worth posting every time I change a single component. So, here's a few group changes that have happened!

 

[2dbit]

C48 should be 25uF....