Eros 2 final voltage check — high values (FIXED)
- Thread starter Lowercase
- Start date
Paul Joppa
Moderator
Running low on things to check :^) is the emitter grounded? Is the transistor correctly oriented? Somehow the EF86 cathode current needs to get to ground, and it isn't.
Getting 0 when ground to emitter is tested. Yeah it’s oriented correctly. Tabs match up to the PCB, both to the left when looking above.
Since the circuit checks does that possibly mean tubes since you mentioned it earlier?
Noticed couple minutes after unplug OkC has 4.3, but OkD has .7 volts. Anything there?
Since the circuit checks does that possibly mean tubes since you mentioned it earlier?
Noticed couple minutes after unplug OkC has 4.3, but OkD has .7 volts. Anything there?
Re-Soldered the a/b pins and the C4S board. Plugged it in and same voltages again. Checked the ef86 tubes. Very very faint glow, but are warm to the touch. Photo below of tubes on:
https://i.imgur.com/my5FexG.jpg
Also, the getter has a more opaque ring around it unlike the 6922. They were like that when I got them though. Image below:
https://i.imgur.com/SZ7UCXJ.jpg
Keep looking over and rewarming anything that doesn’t look 100% perfect. Also retesting after doing a round and keep getting the same results without anything budging, same voltages in the second post.
If you need more images let me know.
https://i.imgur.com/my5FexG.jpg
Also, the getter has a more opaque ring around it unlike the 6922. They were like that when I got them though. Image below:
https://i.imgur.com/SZ7UCXJ.jpg
Keep looking over and rewarming anything that doesn’t look 100% perfect. Also retesting after doing a round and keep getting the same results without anything budging, same voltages in the second post.
If you need more images let me know.
Paul Joppa
Moderator
I'm not sure what you mean by "opaque" - the getter flash is usually silvery but you can't see through it. The nearest EF86 does appear to have a whitish getter deposit at the top of the tube - unless that's a reflection? That would be a sign of a bad tube that has leaked air. I'm skeptical abput that being the problem though. I'll keep thinking about it.
Pale silver/white would probably be the better description. I know that all white no silver is bad, seems like a portion is halfway there. And nope, no reflections, the other EF86 looks about the same as the closet one too. Can get some better photos from above if you want. Wish I had an easy way to test them, but no tube tester! Does the photo with power on look correct? I guess the manual wasn't joking when it said dim!
Appreciate all the help, really looking forward to installing it in my system!
Appreciate all the help, really looking forward to installing it in my system!
I have seen many EF86s with getters that look like that and worked just fine. I would guess it's something specific to that particular production line.
It is a bit of a stab in the dark, but it may not hurt to replace the 2N2222A transistors. In order to do this, you should get a spring loaded solder sucker (the blue/yellow one that's $20 will work fine).
Cut the transistors off from the board with side cutters, then heat the bottom of a joint with the soldering iron and use the spring loaded sucker to suck out the solder and the lead.
I have on a few occasions seen those transistors fail when I've made a wiring error here and there.
-PB
It is a bit of a stab in the dark, but it may not hurt to replace the 2N2222A transistors. In order to do this, you should get a spring loaded solder sucker (the blue/yellow one that's $20 will work fine).
Cut the transistors off from the board with side cutters, then heat the bottom of a joint with the soldering iron and use the spring loaded sucker to suck out the solder and the lead.
I have on a few occasions seen those transistors fail when I've made a wiring error here and there.
-PB
Replaced the 2N2222A transistors and some exciting results to report!
IA 210-230V 217V
IB 210-230V 217V
OA 155-185V 153V
OB 155-185V 151V
OC 95-100V 100V
OD 95-100V 101V
OkA 95-105V 101V
OkB 95-105V 103V
OkC 0.7-2V 1V
OkD 0.7-2V 1V
Still some slightly under and over optimum, but within 10%! Can’t wait to hook it up. Thanks to both Pauls for helping diagnose!
IA 210-230V 217V
IB 210-230V 217V
OA 155-185V 153V
OB 155-185V 151V
OC 95-100V 100V
OD 95-100V 101V
OkA 95-105V 101V
OkB 95-105V 103V
OkC 0.7-2V 1V
OkD 0.7-2V 1V
Still some slightly under and over optimum, but within 10%! Can’t wait to hook it up. Thanks to both Pauls for helping diagnose!
