An error in the C-Line and TR-4C CDs has been brought to my attention.
The error is in the T-4XC and TR-4C Relay Replacement Sheet. It SHOULD read as follows.....
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Replacing the T-4XC Relay The "correct" replacement relay is the P&B (Tyco) R10-E1-Y4-V2.5k, same relay used in the "late" T-4XC and TR-4C, which IS available from Mouser and Digikey among others. Currently about $25. If your old relay is a Varley with a 15k coil, you need to look at the socket for V19, the 6FQ7 (or 6EV7). If there is a 1.5k, 1W resistor connected between Pin 1 and Pin 9, just plug in the new relay. If there is NO resistor, remove the wire connected to Pin 1 and move it to Pin 9, add a 1.5k, 1W resistor between Pin 1 and Pin 9, and plug in the new relay. The 15k ohm coil relays were failure prone, primarily because of the very fine wire needed. The bobbin would swell, especially in humid conditions, stressing and breaking the wire. This is why T-4XC's that have been stored in the garage for a while often have a bad relay! The 2.5k ohm coil of course uses considerably larger wire.
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I don't know where the reference to Pin 6 came from, it's not on any of my reference notes. Guess it just goes to show that you can never have too many (enough?) people proof-read your writing....
I'm very sorry for the error, and will be happy to send a corrected PDF for any who wish to add it to their CD. Some CD writing software will allow you to add files, some will not.
-- 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs <www.k4oah.com> _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
