HP-Service-Note-523DR-2 电路图.pdf

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1、523DR-2 b MODELS 523CR/DR ELECTRONIC COUNTERS SERIAL NO. 010-00425 AND BELOW CONNECTIONS FOR STANDBY OPERATION OF CRYSTAL OVEN Crystal ovens in Models 523CR/DR Electronic Counters under control of the front panel power switch can be easily connected for standby duty, so the oven will remain on when

2、the power switch is turned off. After modification, the Operating and Servicing Manual for instruments with serial number prefix 319- will be correct for your instrument. The 319- manual was supplied for most instruments with serial number prefix 010. Instruments already connected for 115 volt stand

3、by operation have a resistance of about 1000 ohms across the power cord terminals when the instru- ment power switch is off; those aranged for com- plete turn-off will give an open reading, winding to terminal A2, through the shielded cable to the power on-off switch S201, through the fuse F202, and

4、 back through the shielded cable to the other wire of the power cord. Itmay be necessary to reverse the cable wires at S201 and F202 to obtain this sequence. 4) Cut to length and connect the white wire for the crystal oven heater element to terminal A1 of the power transformer. 5) The other terminal

5、 for the crystal oven heater element must be connected to the junction of S201 and F202 through a shielded wire. If you add this shielded wire, run it along the existing shielded wires which run from the oven to S201 and F202. Ground the shield at the tiepoint for the power cord. This completes wiri

6、ng. 6) Check power cord circuit resistance. Circuit should measure open when front panel fuse F202 1) Remove instruments top and bottom covers. is removed, about 1000 ohms when Power switch is off (fuse in), and about 10 ohms when power switch 2) Locate the two wires (usually white and black- is on,

7、 based on 115 volt operation. white) which supply 115 vac to the crystal oven heater element. The white wire terminates on the tiepoint terminal strip for the power cord; discon- nect the white wire at this point. The other wire may be connected to terminal A1 of the power transformer; if so, remove

8、 it, In some instru- ments, this wire is connected to the junction of the power switch and fuse on the front panel; if SO, leave it connected. DO not remove jumpers b WIRING PROCEDURE - 0 1 on crystal oven terminals. TIEPOINTS 5 AMP ON-OFF .- S LO-BLO 3) Trace the primary power circuit. The con- nections must be in the following order: From the black wire of the power cord to terminal A1 of the power transformer, through the primary of Crystal Oven. Figure 1. Connections for Standby Operation I L - I distribution abcefg 00735-2 COMPLETE C , BhECfRONIC MEASURING RadioFans.CN 收音机爱 好者资料库