Almost there, but strange problem [resolved]

[BrettMatthews]

Hi, I am the new owner of a second hand Bottlehead crack. The previous owner sold it incomplete as he was not able to figure out the problem (was blowing the fuse). Uppon arrival I immediately saw a couple issues (major one being the red wire off the transformer terminal 9 going to terminal 20 instead of 19). So I corrected that and a couple other things along with a lot of bad quality solder. Next step was the resistance checks and that's where I found this problem.

So for the problem, all the resistance checks check out except for terminal 13 where instead of climbing to 270k it starts at about 6M and goes down.

Since finding this problem I have quadruple checked the diode orientation and the capacitor orientation. I have also tested the diodes and all four still bias in one direction and have high impedance in both directions. Next I desoldered everything from terminal 12 and 13 and put everything back together with the same problem. I also checked the value of the capacitor on 12 and 13 when it was off and the resistor and both had proper values.

I have also changed the power transformer it was smoking and crunchy under the black material with a spare power transformer that was included in the sale. I haven't powered it on since the new ptu was installed as I want to sort this resistance issue first.

Any help is greatly appreciated!

 

[Paul Birkeland]

From the manual regarding terminals marked with an *:

"The values signified with a * are going to vary from ohmmeter to ohmmeter because these terminals are connected to the filter capacitors, which try to charge themselves off the battery in the meter, causing a fluctuating reading.  If the circuit is connected properly, these readings will wander in the tens or hundreds of Kohms or higher range.  What you want to watch out for is a zero reading at one of these terminals, which would indicate that something is miswired"

 

[BrettMatthews]

From the manual regarding terminals marked with an *:

"The values signified with a * are going to vary from ohmmeter to ohmmeter because these terminals are connected to the filter capacitors, which try to charge themselves off the battery in the meter, causing a fluctuating reading.  If the circuit is connected properly, these readings will wander in the tens or hundreds of Kohms or higher range.  What you want to watch out for is a zero reading at one of these terminals, which would indicate that something is miswired"

Thanks for the response. I did see that but I guess I read it to literally then, where is says will climb to 270k I thought it would start low and climb up to 270k instead of starting high and decreasing. But I'm happy if this isn't an actual problem.

 

[BrettMatthews]

Well good news, its working! Going to leave it stock for a little while and then install the Speedball (already have it).

 

[Nathan]

Yeah! ANother succesful build!

 

[BrettMatthews]

Well it's safe to say it sounds awesome! Still going to leave it stock for a little while, after that I'll install my Speedball kit. Does anybody have any other recommendations that make a good sized difference with the HD600?