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Author Topic: SB 220 Not so much a new topic but a second request for information  (Read 1166 times)
GM6WCF
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Posts: 28




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« on: April 01, 2013, 07:34:24 AM »

Heathkit SB220. I'm selling one on and it would be good to know if it is possible to date it by reference to any internal components or by any other method.

Thanks in advance

Dave B
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W1QJ
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« Reply #1 on: April 01, 2013, 07:50:53 AM »

Well I can tell you if it is a beginning model which were the VERY first to me sold, or if it was the second run or if it was the latest run just before the SB-221 came in.  Here's how.

The very earliest SB-220 (which would be the very oldest) will have a Zener diode directly on the rectifier board.  If it has a Harbach upgraded rectifier board, check to see if there is a zener hole on the  middle chassis just adjcent to the top left of the rectifier board.  It will have a broadcast type of load cap.  It will have grren doorknob caps

The second run of SB-220 amps would have a zener diode remoted on that middle chassis.  It will have a broadcast type of load cap. It will have green doorknob caps, if red doorknobs and broadcast load cap it would be the latest of that run.

The last run of SB-220's (just before the SB-221) would have a load cap which resembles the tune cap with many more plates. It will have red doorknob caps.
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GM6WCF
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« Reply #2 on: April 01, 2013, 12:49:20 PM »

Thank you for the info. It's too late tonight to reopen the amp., so I'll look tomorrow.

I have just noticed and photo'd the label on the rear panel which has a serial number SB220 120 123106.

Dave B
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Decidophobic - Formophobic - Xenophobic. All of which make it very difficult to start a new topic that will be read and likely commented on by Elmers of grouchy inclination.
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