[time-nuts] 5370A vs 5370B
Bob Camp
lists at rtty.us
Wed Mar 10 01:52:25 UTC 2010
Hi
I didn't leave it on for very long. IIt would not surprise me if there's some drift that's occurred. It was last calibrated in 2006.
Bob
On Mar 9, 2010, at 8:48 PM, paul swed wrote:
> Bob how long has it been on
> I think it needs to be stable like about 30 minutes
>
> On Tue, Mar 9, 2010 at 8:37 PM, Bob Camp <lists at rtty.us> wrote:
>
>> Hi
>>
>> Ok, the trigger level pots are bent but functional. The one that was stuck
>> works after a bit of readjustment of the knob.
>>
>> All three inputs (ext arm, and the two channels) blink when I put the 10
>> MHz into them. The two with the working pots behave as expected as the pot
>> is turned (trigger in the middle, no trigger on both ends).
>>
>> For what ever reason it seems to think that the period of it's 10 MHz
>> standard is 99.5 ns. In frequency mode it thinks the standard is at 9.998xxx
>> MHz. Obviously it's a little confused ....
>>
>> Sounds like it's worth working on, unless the 99.5 ns thing indicates some
>> sort of massive failure.
>>
>> Bob
>>
>>
>> On Mar 9, 2010, at 7:03 PM, Mark Sims wrote:
>>
>>>
>>> I've had the "pleasure" of fixing way too many 5370A and 5370B front
>> panels. It's been a while so these musings may be clouded... also beware
>> of the two or three different front panel designs. Also there are "hybrid"
>> 5370A's out there with 5370B front ends.
>>>
>>> There are 4 pots on the front panel: the 470K display update rate, a
>> 10K or 200 ohm arming level (200 ohm on 5370B and later 5370A's), and two
>> 5K trigger level. All are linear taper, all have switches, all are small
>> pots with (1/4"? bushings). Finding pots with proper switches ain't easy.
>>>
>>> I have never had to do the trigger level pots. They have metal shafts
>> and seldom break. Their switches are what you would expect (closed when the
>> pot is turned clockwise). In the far CCW direction the switch is open and
>> selects the 0V trigger level.
>>>
>>> The other two pots are an exceedingly crappy hp design. They have
>> fragile plastic shafts and really poor quality switches. The switches need
>> to be closed when the switch is counterclockwise. HP's pots have both
>> normally open and normally closed contacts. Frankly these pots are seldom
>> used and you can use a switchless pot and just hardwire those pads.
>>>
>>> The display rate pots is particularly useless. You can just hardwire it
>> to max.
>>>
>>> The biggest bugaboo in buying a 5370 is the state of the HP custom input
>> amplifier chips. They can be damaged by overloading the input. Blow one
>> and you are screwed. Buy a 5370 with a blown input amp and you are screwed.
>> The 5370A and 5370B used different chips. The 5345A counter is a source
>> of input amp chips.
>>>
>>> It would be VERY nice if some clever person built drop in replacement
>> "chips" built of modern SMD parts on a DIP header. Those input amp chips
>> are socketed. They are little more than a comparator.
>>>
>>> Quick check of the 5370A inputs is to set the unit to "SEParate" inputs
>> and connect the back panel 10 MHz ref signal to each of the inputs. The
>> signal level LED should flash. A steady LED means that input is toast (or
>> the input PCB slide switches are full of navel lint and need cleaning).
>>> _________________________________________________________________
>>> Hotmail: Free, trusted and rich email service.
>>> http://clk.atdmt.com/GBL/go/201469228/direct/01/
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
More information about the time-nuts
mailing list