I've seen that George, But using the MC100 will not replicate the same function as in the HP8640
as the device in question has a 2 input AND gate at the input and that was use to gate the counter.
If it was U1 which had died I could use a MC100 as the input on U1 is not gated , unfortunately the full function of the device was used
in U4 position. The MC100 has a differential input, and doesn't follow the same function as an AND gate..
I could remove U1 and use that as a replacement for U4, use a MC100 to replace U1 , bypassing the output stage U2 which is the EECL to ECL conveter
Thanks
Richard g8jvm
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On 05/12/2020 15:20, george edmonds via groups.io wrote:
Hi Richard
HP did not originally use standard ECL they used there own version.
Look at some of the information on the 8640, there are details as to how to use standard ECL instead.
George G6HIG Dover UK
On Saturday, 5 December 2020, 14:52:58 GMT, Richard <richard@...> wrote:
Hi all
My HP5342A counter 0-500MHz input has died. I've used the manual
downloaded from the Keysite, but
not the best scan , but useable.
I have plenty of input at the input to U4, both the Gate and reset sigs
are at the IC, but all I see out is pulses which are the same as the
reset pulse on pins 4 & 6,
Nothing on the output of the board.
So I guess the device is dead . its a HP special , also used on the
HP8640 sig gens in the divider stages,? HP 1820-0736?? ECL divide by 2
with an and gate on the input.
the rest of the counter is working OK counts up to 18GHz, As the reset
pulses are visible on pins 6 & 4 , there is cat in hells chance the
input gate maybe be all thats damaged on the IC
it maybe possible to swap U4 and U1, but that is a far from easy process
due to the through hole plating that HP used back then and it would all
depend on if there is enough leakage
though the defective gate for the divide by 2 to clock , its in the last
resort category :(
Has anyone got one of these ICs , or a A3 board or a scrap board from a
HP8640 I could extract the IC from ????
This is NOT for commercial use , I use the counter as part of my hobby
Ham radio
TIA
--
? Best wishes /73
? Richard Bown
? Email : richard@... <mailto:richard@...>
? HTTP? :
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--
Best wishes /73
Richard Bown
Email : richard@...
HTTP :
######################################################################
Ham Call: G8JVM . QRV: 50-432 MHz + Microwave
Maidenhead QRA: IO82SP38, LAT. 52 39.720' N LONG. 2 28.171 W
QRV 6mtrs 200W, 4mtrs 150W, 2mtrs 300W, 70cms 200W,
Microwave 1296MHz 110W, 2320MHz 100W, 5760MHz 10W & 10368MHz 5W
OS: Linux Mint 20, on a Dell Inspiron 3580 laptop
######################################################################
