Geert Samuel
New member
- Joined
- Dec 27, 2014
- Messages
- 3
This BOM can be used with PCB Grinder’s PQ2 boards?
They are back in stock.. I might order one… but I need to find the BOM
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Build Thread:PQD2
- Thread starter Gustav
- Start date
Help Support GroupDIY Audio Forum:
They are back in stock.. I might order one… but I need to find the BOM
raoul1983
Member
does anyone know what resistor should be in de DROP? I've ordered a few, but I don't know how to figure out which one should be there.
raoul1983
Member
figured it out ;-)
But I Have another question.
I've isolated the LM317. But the middle pin is still connected to the bottom plate witch makes contact with ground, is that right? Or shouldn't that be happening? If not, how should I handle the isolation than?
Also when testing with the tubes installed (they glow) I got around 265V before the drop resistor and 0v after the drop and the Drop resistor starts to smoke... Not entirely sure it was smoke from this resistor, but something smoked.
When I do a continue measure, it seems that ground and 12.6v (measure point on the V3 board) is connected, I don't see any solder bridges, what could this be?
Hope you can help me out.
But I Have another question.
I've isolated the LM317. But the middle pin is still connected to the bottom plate witch makes contact with ground, is that right? Or shouldn't that be happening? If not, how should I handle the isolation than?
Also when testing with the tubes installed (they glow) I got around 265V before the drop resistor and 0v after the drop and the Drop resistor starts to smoke... Not entirely sure it was smoke from this resistor, but something smoked.
When I do a continue measure, it seems that ground and 12.6v (measure point on the V3 board) is connected, I don't see any solder bridges, what could this be?
Hope you can help me out.
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raoul1983
Member
To be sure I rebought another set of bridge diodes, another LM317 with heatsink (because its shorting to the case even with iso pad)
Also ordered other tubes, I have the EC88 while it should be ECC88 .....!
Hope it will be solved with this all.
If anyone have other ideas, please shoot!
Also ordered other tubes, I have the EC88 while it should be ECC88 .....!
Hope it will be solved with this all.
If anyone have other ideas, please shoot!
You need not only the iso pad, but also a nylon insert for the hole where the screw goes, to keep it isolated..
raoul1983
Member
Ahh, of course! Or a nylon screw would also be possible I guess.
Ground and 12.6v shouldn't be connecting right? (it's too obvious, but still..)
Ground and 12.6v shouldn't be connecting right? (it's too obvious, but still..)
raoul1983
Member
Its working!!!
The power board at least, still waiting on the transformers...
To be curtain I changed the two bridge diodes, and the LM317.
Put in the correct tubes.... ! (mis read the first time)
Had to paralel the resistor, to get a nice 230v.
Tapped power from the 12.6v with a transistor for the power on/off LED
I hope this heat sink is enough. Or is this a no go?
The power board at least, still waiting on the transformers...
To be curtain I changed the two bridge diodes, and the LM317.
Put in the correct tubes.... ! (mis read the first time)
Had to paralel the resistor, to get a nice 230v.
Tapped power from the 12.6v with a transistor for the power on/off LED
I hope this heat sink is enough. Or is this a no go?
Attachments
raoul1983
Member
Finally received the transformers.
left channel works great, right channel doesn't work, There seems to be output but I have to set the levels (after the pq2) very high
Any hints of were to look for the problem?
It doesn't seem to be the in/output xls connections or the connections to the filter board (I think).
Ok, I just swapped the tubes, and now the other channel is working.
so it's probably the tube..
I guess I should just order an other one right?
If there's something else I should check or do, please let me know ;-)
left channel works great, right channel doesn't work, There seems to be output but I have to set the levels (after the pq2) very high
Any hints of were to look for the problem?
It doesn't seem to be the in/output xls connections or the connections to the filter board (I think).
Ok, I just swapped the tubes, and now the other channel is working.
so it's probably the tube..
I guess I should just order an other one right?
If there's something else I should check or do, please let me know ;-)
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That sounds pretty straightforward. Sometimes you just end up with a bad tube. It seems to me that you've found the problem.
raoul1983
Member
I've ordered them matched this time, hope there's no bad one this time, it's a bit more pricey ;-)
joshk34
Active member
Just hoping to get a couple clarifications. The BOM's that have popped up have specified for 330uf 400v caps for the supply. However in Gustav's build guide they seem to be 220uf 400v. Does it matter, or is it related to the specific power supplies used?
Also, I seem to be getting multiple different values for the large high voltage WIMA caps by the tubes? Is there one that works, 4u7f or 6u8f. I see there's a range on the PCB, but just don't know enough yet, to deduce which.
One last thing, is there any specs on the fuse required? I believe the G-Pultec was a 250ma Slo Blow, is that still correct?
Thanks for any help!
Also, I seem to be getting multiple different values for the large high voltage WIMA caps by the tubes? Is there one that works, 4u7f or 6u8f. I see there's a range on the PCB, but just don't know enough yet, to deduce which.
One last thing, is there any specs on the fuse required? I believe the G-Pultec was a 250ma Slo Blow, is that still correct?
Thanks for any help!
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joshk34
Active member
Sorry to bump, just need these last pieces and I just have to wire. Any insights to help with my ignorance.
220 or 330uF caps for the PSU will both be perfectly fine.
And anyting in the range will be fine on the large WIMA cap.
Gustav
joshk34
Active member
Thanks so much!
Got it all wired, flipped it on and the led came on for a split second then went off. Took the measurements, you see and found some continuity between the LM317 and the case, despite the pad and plastic washer. Furthermore, still found continuity even when I picked the LM317 off the case. Im guessing this shorting is causing the readings I’m seeing as well as the LED not to work. I’m struggling to isolate it.
Got it all wired, flipped it on and the led came on for a split second then went off. Took the measurements, you see and found some continuity between the LM317 and the case, despite the pad and plastic washer. Furthermore, still found continuity even when I picked the LM317 off the case. Im guessing this shorting is causing the readings I’m seeing as well as the LED not to work. I’m struggling to isolate it.
Attachments
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Could be that you measure through the heater to ground? Try measuring without tubes in sockets?
