HammondWiki - Diff: TSB #27

Differences between current version and predecessor to the previous major change of TSB #27.

Other diffs: Previous Revision, Previous Author

Newer page: version 3 Last edited on February 15, 2003 8:19 am. by JeffDairiki
Older page: version 1 Last edited on August 12, 2001 10:07 am. by
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-!Technical Service Bulletin # 27  
-January 28, 1966%%%  
-Affects Models M, M-2, M-3, S & S-1  
-As noted in our previous technical bulletin #8, the early electromagnetic speakers are becoming more difficult to recondition as regards to increasing prices and the availability of proper materials.  
-With proper circuit revisions, the AO-21066-1 and AO-21055-2 electromagnetic speakers, as used in the early Spinet and Chord organs, can be replaced with our AO-22748-0 permanent magnet speaker, selling at a list price of $14.00.  
-In place of the AO-21055-1 EM speaker field coil, a 1000-ohm 20-Watt resistor must be subsituted. For the AO-21055-2 EM speaker field coil, a 700-ohm 20-Watt resistor must be substituted.  
-One other revision must be made to the early Spinet and Chord organ power supply circuits.  
-In the case of the Model M Spinet, condenser C-57 .15mfd must be removed. Install a 25mfd 25WVDC electrolytic condenser between the -18 volt point and the chassis ground. This is applicable on all amplifiers of the Modem M Spinet Organ only. The Model M-2 and M-3 will not require this change as a 25mfd condenser is already incorporated in their circuits.  
-In the case of the S and S-1 Chord Organ, condenser C-240 .2mfd must be replaced with a 25mfd 25WVDC electrolytic condenser.  
-NOTICE: In both cases, the POSITIVE side of the 25mfd condenser must be attached to ground potential.  
-No other circuit changes will be required in either of the above  
-models. all wiring and replacement must be done in a neat workmanship manner which reflects your service ability and knowledge.  
-We will begin shipment of the AO-22748-0 PM Speaker soon as our stock of EM speakers is depleted. there will be no allowance for returned AO-21055-1 or AO-21055-2 speakers against this replacement.  
-All old EM speakers speakers AO-21055-1 and AO-21055-2 from prior exchanges, must be in our hands no later than 30 days from the date of this bulletin or from the date of an invoice to receive proper credit.  
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