Dark LEDs and Failed VDC check [resolved]

[setterp]

Finished the Eros 2, but failed final voltage checks.

Dark LEDs at D1D and D2D, LEDs at D1B and D2B seem to dim (go out) after 15-20 seconds.

VDC as follows:
IA 218V
IB 220V
OA 159V
OB 218V
OC 96V
OD -0.4V
OkA 98V
OkB 8.2V
OkC 1.8V
OkD 0V

Tried swapping EF86s from side to side, no change.

Picture attached, can provide additional.

Any/all help appreciated.

 

[Paul Birkeland]

The 0 ohm jumpers on the EF86 socket need to cross over each other so that the leads don't touch. Just looking at your one photo, it looks like they might be touching on both sides. This could make a 0V condition at OkD on its own.

There are also a bunch of solder joints which don't look to have been adequately flowed out.

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[setterp]

Paul-

Thank you for the response.

I went back and checked the jumper resistors and confirmed that they are not touching on the A and B sockets. I also reflowed the C4S board.

It appears that I mis-measured the OkD earlier. It is reading 100mV and climbs.

Also I am still seeing the D1B and D2B LEDs light up strongly on startup and then dim and go out entirely after 15-20seconds from startup.

Any thoughts would be appreciated.

 

[Paul Birkeland]

Can I see what the top and bottom of your Eros C4S board look like?

It's most likely that the center leg of Q2B is insufficiently soldered.

 

[setterp]

Eureka!!!!

I pulled the C4S board off, and you were absolutely right the center leg of Q2B was insufficiently soldered. Touch it and a few other joints up.

Reinstalled the board, plugged it in with full LEDs and a perfect voltage check!!!

Thank you SO very much Paul! Looking forward to putting the Eros2 into my system and enjoying some music with my family for the holidays!

Merry Christmas Mr. Paul, you are such an important part of the bottlehead community! Forever in your debt.

 

[setterp]

Well my excitement was short lived…

Installed the Eros into my system, put on one of my favorite albums and got very little sound from my speakers. If I put my ear right against the tweeter I can hear a whisper of sound, but it is very low.

Quick description of my system:
Audio Technica LP70x
AT-VM95ML cartridge
Bottlehead Eros2
Bottlehead Smash preamp
Pioneer power amp

I am admittedly new to turntables, and had to improvise with a home ground wire with standard RCA between the turntable and Eros. Could this be the issue or is there something else going on?

 

[Paul Birkeland]

If all your voltages look good, then be sure you don't have solder shoring out one of your input or output jacks, and double check that the jumpers are present on the two front/center 5 lug terminal strips.

 

[setterp]

Thanks again Paul.

I should have mentioned that the very low sound level was from both speaker and the same low volume.

I will give it look over tomorrow morning, and report back.

Really surprised I am having so much trouble. My Crack w/ Speedball and Smash w/ Smash-up builds went flawlessly several years back (not a single issue). I guess I lost my touch.

 

[Paul Birkeland]

There are a lot of parts in an Eros, I frequently end up debugging my own when I end up building them.

 

[setterp]

We have music, and it sounds wonderful!!!

Took the Eros back to the bench and verified resistance and voltage checks. Both passed with flying colors.

Felt iffy about my ground wire (turntable->Eros) so remade a cable with proper spade connectors.

Put the Eros back in the system, and she’s now making beautiful music.

Thank you again for the help Paul, wishing you the Merriest of Christmas’