Bottlehead Forum
Bottlehead Kits => Eros Phono => Topic started by: Kmmm on November 11, 2013, 11:26:08 AM
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Hi
Just finished putting together my Eros and I thought I got some strange readings on my CS4 voltage check.
The resistance check was OK (on the high side) The Shunt reg was OK. http://www.bottlehead.com/smf/index.php/topic,5129.0.html
(http://www.bottlehead.com/smf/index.php/topic,5129.0.html)
All LEDs are lit. But the two LEDs on the A side of both CS4 boards are a lot weaker then the ones on the B side.
Voltage readings are:
IA A side: 224V B side: 223V
Kreg A side: 0,6V B side: 0,6V
breg A side: 203V B side: 195V
OB A side: 201V B side: 193V
ba A side: 0 B Side: 0
OA A side: 222V B side: 221V
IB A side: 224V B side: 223 V
Some of the values are way of the manual (page 77) and I''m a bit worried.
All feed back is highly appreciated.
Cheers
Kaare
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Any thoughts? any one ???
I just bought myself a new voltmeter.
These are the new measurements:
kreg A: 0,58V B: 0,38V
OB A: 193V B: 150V
breg A: 196V B: 153V
OA A: 221V B: 220V
IA A: 223V B: 223V
The LEDs are still dim on the A side of both boards...
I did hook it up to my Stereomour and there where quite audible white noise in both left and right speaker.
My turntable is not up and running at the moment, so I have not tested with signal.
I must have messed up :-[
Any thoughts as of where to start searching would be most appreciated.
Kaare
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No current is being drawn through the C4S loads. This can happen if the tubes aren't being heated (that's the 6.3V feed), from a missing ground connection to the C4S boards or from the power supply, etc.
Essentially, you very likely have missed something. You can post pics up here and we might be able to eyeball what's up.
-PB
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Thank you for your reply!
Everything was meassuring OK on the PS board and the Shunt reg. board.
I guess I should start going through everything from that point?
I'll try to post some pictures as soon as I have a chance.
Cheers
Kaare
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Here are some pics
As you can tell the output caps have been changed.
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I can immediately tell that you have 270K resistors where you should have 27K resistors. The 27K resistors and 270K resistors are incredibly visually distinct, having both different stripe colors, different body colors, and different sizes.
Are the 27K resistors on the power supply PCB?
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Oops !
Nicly spotted. Thank you.
The 27k sits on the PS PCB
I'll change them around this weekend.
Do you think it might have done any harm to other components?
K
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Do you think it might have done any harm to other components?
Probably not, but it would certainly prevent the 6922 from operating properly, and since there is a servo loop that uses the 6922's operation to control the EF86, it it entirely possible that this is all that's awry.
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Hi
Swopped the resistors around and I think it turned out OK.
Voltage is spot on all over except for Kreg on both CS4 boards where it's 1,5V.
is that OK?
Kaare
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Yeah, 1.5V at Kreg is a great voltage to have!
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Thank You so much for your support! ;)
Kaare