[CQ-Contest] Modify AL-1200 HV Power Supply by adding 2 capacitors & bleeder resistors

[w5wz at w5wz.com]

Ray W2RE was with me in the Dayton flea market around 2010 or 2012 when 
I saw this AL-1200.  He told me he had a couple, and they were good 
contesting amps.  So, I bought it.  Turns out, his call sign is again 
associated with this amp as I've had to repair/modify its HV power 
supply and sought info online.


WARNING – LETHAL VOLTAGES!!! DO NOT ATTEMPT WITHOUT PROPER SAFETY 
PRECAUTIONS!!!  I’m not responsible for what you do with this 
information!

The Ameritron AL-1200 has a 3,600v power supply. Its filter capacitor 
bank of eight, 270mF 450vDC runs right at the limit of its design (8 x 
450 = 3600). A common modification is to add two additional capacitors, 
along with the needed bleeder resistors, to increase the filter bank 
capacity to 4,500v (10 x 450=4,500). Keep in mind that the transformer 
still puts out 3,600v, so this modification essentially allows the 
components in the filter bank to have some overhead capacity.

W8JI and W7RY both offer a replacement PCB designed for 10 capacitors.

W1QJ described the way he modified an AL-1200 for W2RE here:
https://forums.qrz.com/index.php?threads/al-1200-power-supply-project.369641/

I choose to adopt the W1QJ method, and show how I did in the W5WZ blog.  
This will also work in the AL-1500 equally well.

https://www.w5wz.com/2019/09/modify-al-1200-hv-power-supply/

--Scott, W5WZ