Channel Sudden out (A Side) [resolved]

[svEnchantment]

Paul,

Thank for the directions. I will do that this weekend and report back when completed with the results.

Good Weekend !

Cheers

Bob S

 

[svEnchantment]

Good evening Paul,

So I have reversed the C4S 180 degrees (See Picture, makes a mess of the board !)- Little harder than I thought this would be.



Following are the key measurements on the C4S board - (basically the same)

IB = 399.8  OB = 178.4  IA = 399.9  OA = 382.1  Both Kregs = 2.498.

A1-4, C1-4 fundamentally the same.

I hope this helps with the next steps or answers.

Thank you and I await the next instructions.

Cheers

Bob S

 

[Paul Birkeland]

I would go ahead and replace the C4S board.

 

[svEnchantment]

Paul,

Just to follow up here -- I have ordered the replacement parts from Eileen. Below is what she asked to forward back to her. Looking forward to her getting those out to me and getting this completed. Will update you when completed and tested. Thank you again for the assistance and help here on getting me to this to this stage. This exercise has, as you might expect, has given me a further insight into the design and workings of these amps/preamps. Appreciate it !!!

1 - C4S PCB
4 - HLMP-6000 LED
2 - 237 ohm 1/8w metal film resistor
2 - 300K ohm 3w resistor
2 - 2N2907A transistor
2 - MJE5731A transistor
2 - LM431 regulator

 

[Paul Birkeland]

We don't stock the 2N2907 anymore (I think).  If you end up with PN2907 transistors, be aware that they look about identical to the LM431A regulator, so be careful not to mix them up.  The PN2907 goes into the 2N2907 holes with the rounded side of the transistor facing the little flag tab on the board outline. I've attached a picture of what this should look like, but if you have any lingering uncertainty just pop on here and let us know.

 

[Doc B]

Yup that is correct, PN2907 is the current stock.

 

[svEnchantment]

Paul,

I received my new C4S board/parts on Wednesday. I got time today to put the new board in place. It was quick and easy. Checked the key voltages and all is well.  Put AMP back in service and is playing as sweet as it always has. Have had playing a good part of the afternoon and evening.

I want to thank you and all of the Bottlehead team for continuing to support your products whether new or 10 or more years old,  it is a testament to your customer care and what makes Bottlehead a great company.

I ordered a Crack+Speedball this past September and look forward to finally getting to work on this kit early next week.

I still am holding out for the MonAmour, hoping it comes back into availability. I want to take this Stereomour amp and move it to a 45 but love the 2A3 tube such that I don't want to not have one in my collection of amps.

Again Thanks and Happy Holidays

Cheers

Bob S