Final voltage check on the Eros 2.0

[87Coug]

Hello all, I just completed the final voltage check....IA 220.3v, IB 220.3v, OA 158.5v, OB 128.2v OC 97.3v, OD 60.3v, OKA 98.5v, OKB 62.2v, OKC 1.512v, OKD 0v. LED D1B not lit. I read thru the previous posts regarding this and reflowed all the solder joints from top of the C4S board. I then checked the tube sockets C1,C2,C7,A6,B6,B9 and A9 for the correct 90.9 90R9F ohm resistor and all checked to spec. OB,OD,OKB and OKD all failed and are on the R side of C4S board as you look down......Is this coincidence that they all are on the right side of the board? Im unsure of what to check and or test next, any help would be appreciated. Regards, Jack

 

[87Coug]

Update, I reflowed the 4 misbehaving solder joints and all but 1 in compliance now. OB was 128.2v now 101.3 and LED D1B still not lighted. Soooo down to just OB and LED D1B.......... again any input appreciated. Jack

 

[Paul Birkeland]

The 0V on OKD is a big problem. Can you carefully measure the voltage between pins 4 and 5 on the EF86 socket being fed by that half of the board? You want to be sure that the EF86 is being heated so it can conduct, and if you don't see ~6.3V appearing there, then that would cause the exact issue you're having.

Another issue you could have is if the 2N2222 transistor on that side of the front C4S is installed right up against the PC board, which could allow for the metal case to be shorted to some of the other pins, and that will give you 0V there as well.

 

[87Coug]

The 0V on OKD is a big problem. Can you carefully measure the voltage between pins 4 and 5 on the EF86 socket being fed by that half of the board? You want to be sure that the EF86 is being heated so it can conduct, and if you don't see ~6.3V appearing there, then that would cause the exact issue you're having.

Another issue you could have is if the 2N2222 transistor on that side of the front C4S is installed right up against the PC board, which could allow for the metal case to be shorted to some of the other pins, and that will give you 0V there as well.

Paul, prior to your post, I reflowed those joints on the right side of the C4S board......OKD is 1.8v, OKB 96.8v, OD 96.9v, only issue left is OB still out of parameter at 100.5v and D1B LED still not illuminated. Thanks again for your input. Ive attached a photo of the PC Board.

 

[Jameson]

I think you a backward component. Circled in red in the attached.

 

[87Coug]

I think you a backward component. Circled in red in the attached.

Excellent eye Jameson, is it possible to reheat and pull that and flip around or should I desolder all the leads and completely remove the board and desolder from the back side?

 

[Jameson]

If you have a wick or solder sucker you might be able to get the component out from the top, but you'd probably have a higher chance of success working on it independently from the rest of the amp. If you need to order a new part altogether Jean and Eric can get you set up.

 

[87Coug]

If you have a wick or solder sucker you might be able to get the component out from the top, but you'd probably have a higher chance of success working on it independently from the rest of the amp. If you need to order a new part altogether Jean and Eric can get you set up.

Got it, appreciate your help

 

[87Coug]

I was able to remove and turn around the resistor, re soldered all the PC board joints and all voltage checks good. Thanks again Paul and Jameson. Please close me out on this one.