12-09-2020, 07:03 PM
Hi Trevor,
In the ones I had to open, the problems were primarily related to the capacitors.
It is perfectly fine to keep using EY51s. No need whatsoever for semiconductor diodes. Although I admit that I used BY8210 (or BY707 - they are in oil anyway) on one or two occasions for other reasons.
Just test the existing three EY51s or replace them anyway if you have new ones in stock.
Despite the also high forward voltage of the BY8210, the waveform is influenced a bit, but this does not seem to deteriorate the functioning.
If you need more space for the replacement capacitors, you can win a bit room by using the BY diodes i.s.o. the EY51s.
Draining the oil through the EHT connection. Just remove the little screw in the threaded flange (of the EHT cable) and remove the flange itself (it is screwed on). After that the rubber stop can be pulled upwards over the EHT cable. You may have to pry a bit with something pointed between the cable and rubber, in order to ease the cable free from the rubber.
The can is made of fairly thin material and is soldered around the top rim. A heat gun, used alternatively on all sides, will melt the solder and the top can be prised loose. The complete transformer assy is with three 3 mm screw to the top and will come out the can with the top.
I think a gas flame will do also - I used this the first time I had to open a can, but it got a bit messy...
Prying it open while using a soldering iron is not a good idea (that T-shirt is also in my possession).
A bit tricky, because of the heat, the glass feed-throughs can unsolder themselves. No problem, they are easily soldered back in place.
Note that they are connected by very thin wire, so be careful not to pull.
I'll see if I can find a few photos of how it looks.
Jac
In the ones I had to open, the problems were primarily related to the capacitors.
It is perfectly fine to keep using EY51s. No need whatsoever for semiconductor diodes. Although I admit that I used BY8210 (or BY707 - they are in oil anyway) on one or two occasions for other reasons.
Just test the existing three EY51s or replace them anyway if you have new ones in stock.
Despite the also high forward voltage of the BY8210, the waveform is influenced a bit, but this does not seem to deteriorate the functioning.
If you need more space for the replacement capacitors, you can win a bit room by using the BY diodes i.s.o. the EY51s.
Draining the oil through the EHT connection. Just remove the little screw in the threaded flange (of the EHT cable) and remove the flange itself (it is screwed on). After that the rubber stop can be pulled upwards over the EHT cable. You may have to pry a bit with something pointed between the cable and rubber, in order to ease the cable free from the rubber.
The can is made of fairly thin material and is soldered around the top rim. A heat gun, used alternatively on all sides, will melt the solder and the top can be prised loose. The complete transformer assy is with three 3 mm screw to the top and will come out the can with the top.
I think a gas flame will do also - I used this the first time I had to open a can, but it got a bit messy...
Prying it open while using a soldering iron is not a good idea (that T-shirt is also in my possession).
A bit tricky, because of the heat, the glass feed-throughs can unsolder themselves. No problem, they are easily soldered back in place.
Note that they are connected by very thin wire, so be careful not to pull.
I'll see if I can find a few photos of how it looks.
Jac
