Starting up amp for the first time ... no voltage reading

gnugear · Post by **gnugear** » Sun Sep 25, 2005 4:18 pm

So this is a brand new build. I've got everything wired up for the first time and I'm at the step where I turn on the amp without any tubes in it. I'm taking voltage readings off of pin 2 and 7 of the output tube sockets and I'm not getting anything. Same goes with the preamp sockets. Any ideas?

BTW, this is with the power on and the standby on ... do I need to turn the standby off?

Flames1950 · Post by **Flames1950** » Sun Sep 25, 2005 4:34 pm

Is this your TrainWreck yet?
What power tranny is it?

gnugear · Post by **gnugear** » Sun Sep 25, 2005 5:11 pm

No, it's a metro build with a Heyboer power transformer and merc OT.

Flames1950 · Post by **Flames1950** » Sun Sep 25, 2005 5:30 pm

If your thick black wires are goin to pins 2 and 7 and you've got nothing, I suppose you could unhook them and see if you get a DC resistance reading. If it's infinity, George will be seeing that tranny again. If it gives you a reading see what voltage they show when they're not hooked up.
Green center tap is hooked up I presume?

gnugear · Post by **gnugear** » Sun Sep 25, 2005 5:54 pm

Well, here's the part of the story that I left out ...

I had the big green wire and one of the big black wires hooked up together by mistake. I heard the sizzle ahd I smelled the insulation cooking and I quickly turned off the amp ... I'm hoping I didn't hurt anything because I grounded the green wire and everything turns on okay ... I'm just not getting any voltage reading.

Do you have a copy of the 100 watt voltage chart?

Flames1950 · Post by **Flames1950** » Sun Sep 25, 2005 8:55 pm

Dude, I'm sorry, but I bet that tranny is toast........ouch.
SoZo had some 100 watt Heyboers in the classifieds really reasonable -- $75 new or $50 used for his personal spec.....I'd get on the horn ASAP with John and snag one.......

gnugear · Post by **gnugear** » Sun Sep 25, 2005 9:34 pm

Ah crap

I might try some more trouble shooting before I give up.

gnugear · Post by **gnugear** » Sun Sep 25, 2005 10:42 pm

Can you hurt aything by running the amp if the PT is burnt?

flemingmras · Post by **flemingmras** » Tue Oct 25, 2005 12:33 pm

Disconnect the black wires from pins 2 and 7 of the output tube sockets and take a voltage reading across them. The reading should be around 6.5-6.8VAC(the reading is that high since there will be no current drawn from them in this test. The normal voltage is around 6.3 with all the heaters drawing current but since they are disconnected, the voltage will be that high). If you get nothing the tranny is toast.

Jon

gnugear · Post by **gnugear** » Wed Oct 26, 2005 12:09 pm

My PT was fried. I installed a new one and it fired up on the very first try. That's a first in my book ... and the amp is smokin good!!!