Bottlehead Forum

Bottlehead Kits => Eros Phono => Topic started by: stingers96 on February 20, 2013, 05:09:19 PM

Title: another Voltage reading problem
Post by: stingers96 on February 20, 2013, 05:09:19 PM

I am building my first kit and everything as going well until i installed the power supply PC board and connected it to the transformer. the voltage was correct when i connected the meter to the 270K ohm resistor and th 270K ohm 5W wire wound resistor (got a reading of 380V) When i unplugged it from the wall it took several minutes for the voltage to bleed off.  I figure thats OK.  But when i plugged it back in and tested the 6.3vDC + pad on the board i got no reading.  I checked all wire solders and they are all sound connections.   

I am at a loss and dont know what to do.  Please help so I can continue my build.

Thanks in advance

Ryan

Title: Re: another Voltage reading problem
Post by: vetmed on February 20, 2013, 05:18:03 PM

Its unclear to me what stage of assembly you are at. I have built 6 or 7 Bottlehead kits and have always waited until assembly was finished to check ohms, never mind plugging something in before assembly is finished. If I have misunderstood please excuse me.


Robert Lees

Title: Re: another Voltage reading problem
Post by: stingers96 on February 20, 2013, 05:19:41 PM

i am on page 44/45 (Power supply voltage test) where the manual instructs you to test the voltage

Title: Re: another Voltage reading problem
Post by: Paul Joppa on February 20, 2013, 05:26:30 PM

Rats, I lost my post. Try again:

1) Check the AC voltage between the PC board terminals marked T4 and T5. This is the transformer input to the heater supply; it should be about 9 volts AC.

2) Check the DC voltage from ground to the striped end of the two diodes at the forward end, near the heat sink and the +/-6.3v terminals. It should be around +10 volts DC.

3) If that doesn't disclose a problem, then measure the voltages at each of the three pins of the regulator chip. Be careful - you don't want to short then to each other, which is way easy to do!

Title: Re: another Voltage reading problem
Post by: stingers96 on February 25, 2013, 05:53:21 AM

Thanks for the quick reply, unfortunately i was drawn away from my build for a few days. After close inspection (with a magnifying glass) i noticed 2 of the 1N5829 Schottky rectifiers were in backwards.  the silver line was almost worn off completely on both .  After removal and re-installation all voltages tested exactly as expected.   Hopefully i didn't blow anything as a result of my mistake.

Ryan