HP 8640B S/N 2350A23618.
Modulation OFF (both AM and FM);
Output set to -30dBm.
INT/EXT (rear panel) set to INT;
connecting REF OUT (rear panel) to COUNTER INPUT (and setting INT/EXT to EXT) the counter reads:
0005.00 in the 0-10 range; 05.0000 in the 10-550 range
005.000 (x10) in the 0-10 range; 5.00000 in the 10-550 range;
05.0000 - overflow (X100) in the 0-10 range; .000000+overflow in the 10-550 range;.
The RF output frequency is correct and has the correct RF output level.
Level indicator works normally.
External counter input works OK in the 0-10Mhz range, but doubles
the reading in the 10-512Mhz range (BUT not if signal is coming from output REF (rear panel) !! as seen before..).
The "wiper" contacts on the round clear plastic rotary switches seem to be all in place: 4 on the back and
3 on the front on the band switch and 2 on the peak&deviation switch.
Connecting an external counter to the sig-gen output and comparing its readings against
the 8640B internal counter leads to the following table:
Range????? generated signal??? INT Freq counter Reads:
256-512??? 512??? ??? ??? ? ????????? 1024
?? ????????????? 256?? ? ? ? ? ? ?? ? ??? ??? 512
128-256??? 256??? ??? ? ? ?? ? ? ?? ? 1024
?? ? ? ? ? ? ? ? 128??? ? ? ? ? ? ? ?? ?? ??? 512
64-128? ? ? 128??? ?? ? ? ? ? ? ? ?? ??? 128
?? ? ? ? ? ? ? ? ? 64??? ??? ? ? ? ? ?? ? ? ? ?? 64
32-64????????? 64??? ?? ? ? ? ? ?? ? ? ??? 128
?? ? ? ? ? ? ? ? ? 32?? ? ? ? ? ? ? ?? ? ??? ??? 64
16-32?? ? ? ?? 32??? ? ? ? ? ? ?? ? ?? ??? 128
? ? ? ? ? ? ? ? ?? 16??? ? ? ? ? ? ? ? ? ? ? ??? 64
8-16? ? ? ? ? ? 16??? ? ? ? ? ? ? ?? ? ? ? ??? 8
? ? ? ? ? ? ? ? ?? ? 8?? ? ? ? ? ? ? ?? ?? ??? ??? 4
4-8? ? ? ? ? ? ? ? 8? ?? ? ? ? ? ? ?? ? ?? ? ??? 8
?? ? ? ? ? ? ? ? ? ? 4??? ? ? ? ? ? ?? ? ? ? ? ??? 4
2-4?? ? ? ? ? ? ?? 4?? ? ? ? ?? ? ?? ? ? ??? ??? 8
? ? ? ? ? ? ? ? ?? ? 2??? ? ? ? ? ? ? ? ?? ? ? ??? 4
1-2? ? ? ? ? ? ? ? 2?? ? ? ? ? ? ? ?? ?? ??? ??? 8
? ? ? ? ? ? ? ? ? ?? 1??? ? ? ? ? ? ?? ? ? ? ? ??? 4
.5-1?? ? ? ? ? ? ? 1??? ??? ? ? ? ?? ? ? ? ?? ?? 8
? ? ? ? ? ? ? ?? ? ? 0,5??? ?? ? ? ?? ? ? ? ? ??? 4
Can some 8640 guru address me to find the fault?
I have service manuals but none for my S/N. Ordered the right one at Aterk Manuals: still waiting for it.
Thanks in advance.
Emanuele.
Emanuele Girlando