[Hammarlund] Voltage Measurements in the SP-600-JX

[Richard Knoppow]

     Those troubleshooting the SP-600 and probably some other older 
Hammarlund receivers should know that the tube voltage charts were taken 
with a Weston model 663, a 1000 ohm/volt meter. When a more modern 
20,000 ohm/volt meter or an electronic voltmeter is used the voltages 
read will be high. Hammarlund specifies the meter as a Weston model but 
there is a later Weston voltmeter with the same model number which is a 
20K ohm/volt meter. If you are aware of this the higher resistance meter 
can be used but the difference in reading will depend on the particular 
circuit and its sensitivity to meter loading.
     The A.C., bias and AVC voltages were taken with a Measurements Corp 
Model 62 VTVM so will read correctly with nearly any electronic meter.
     The on line handbook for the JX-17 version does not mention the 
VTVM for bias and AVC, an error. TM-11 851 which covers many versions, 
specifies the TS-352, this is a VOM with both 1000 ohm/volt and 
20Kohm/volt divider strings, the 1000 ohm/volt is the correct one to 
use. I've found the voltage charts to be quite close.
-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL