gar381
Well-known member
I decided last winter on a cold snowy day that
it was time to recap my old warhorses (my Ampex 440Bs)
Here at the BI Test Kitchen.
I started with the PWAs…
On the record PWA:
The Record card has a dangerous tant cap.. C32. If that bugger goes bad it
Will take out the record head with it…. NOT GOOD !! If you only
Replace one cap in a 440, MM1000 or any Ampex machine that uses this PWA
it’s this guy. The one in circled in RED.
I used a 22/35 Nichicon cap. Mouser part# 647-UPW1V220MDD
Vishay now makes the old Sprague TE series caps, the silver Alum. Electro. guys On these PWAs.
Replace C28 with Vishay 10/25. Mouser part# 75-TE1204-E3
On the reproduce PWA:
Replace C8 with Vishay 50/50. Mouser part# 75-TE1307.
Replace C13 with Vishay 50/25. Mouser part# 75-TE1209-E3
On the Bias PWA:
Replace C44 with Vishay 50/25. Mouser part# 75-TE1209-E3
Next is the Electronics chassis output cap.
Remove the 2 screws on each side that hold the back panel in place.
Remove the screws on the top and bottom of the Black U shaped shield
And expose the back of the PWA connectors.
The big 40+ year old yellow Sprague ATOM 250/50 cap is our new victim.
Ampex part # 5C-15
We could use an axial like the original but one of the nice guys on the
Ampex mailing list suggests to use a Nichicon Radial 470/50
Mouser part # 647-UHE1H471MPD. You got to move some wire around
To replace this guy plus I used a drop of RTV to hold it in place
but this is how it looks:
it was time to recap my old warhorses (my Ampex 440Bs)
Here at the BI Test Kitchen.
I started with the PWAs…
On the record PWA:
The Record card has a dangerous tant cap.. C32. If that bugger goes bad it
Will take out the record head with it…. NOT GOOD !! If you only
Replace one cap in a 440, MM1000 or any Ampex machine that uses this PWA
it’s this guy. The one in circled in RED.
I used a 22/35 Nichicon cap. Mouser part# 647-UPW1V220MDD
Vishay now makes the old Sprague TE series caps, the silver Alum. Electro. guys On these PWAs.
Replace C28 with Vishay 10/25. Mouser part# 75-TE1204-E3
On the reproduce PWA:
Replace C8 with Vishay 50/50. Mouser part# 75-TE1307.
Replace C13 with Vishay 50/25. Mouser part# 75-TE1209-E3
On the Bias PWA:
Replace C44 with Vishay 50/25. Mouser part# 75-TE1209-E3
Next is the Electronics chassis output cap.
Remove the 2 screws on each side that hold the back panel in place.
Remove the screws on the top and bottom of the Black U shaped shield
And expose the back of the PWA connectors.
The big 40+ year old yellow Sprague ATOM 250/50 cap is our new victim.
Ampex part # 5C-15
We could use an axial like the original but one of the nice guys on the
Ampex mailing list suggests to use a Nichicon Radial 470/50
Mouser part # 647-UHE1H471MPD. You got to move some wire around
To replace this guy plus I used a drop of RTV to hold it in place
but this is how it looks: