Frequency counter won't count.

[neo]

At resolution of 100k in check mode

1=4.52
2=4.42
3=4.42
4=3.82
5=3.89
B=1.94
+=132.
the other set of 1-5 is not easily obtainable
Only the three not affected by blanking lit.

UHF mode

1=0.10
2=0.10
3=0.10
4=0.12
5=0.11
B=1.92
+=132.
the other set of 1-5 is not easily obtainable
All lit.

[VK5RC]

I am not much help now,
I have no doubt you will get this.
A tip I got from a great Ham - before switch backon - go for a quick walk out of the room then re-check. If the part is really expensive,  have a cup of tea first. Take lots of photos. Helps later when the labels fall off- don't ask me how......

[Cubdriver]

At resolution of 100k in check mode

1=4.52
2=4.42
3=4.42
4=3.82
5=3.89
B=1.94
+=132.
the other set of 1-5 is not easily obtainable
Only the three not affected by blanking lit.

UHF mode

1=0.10
2=0.10
3=0.10
4=0.12
5=0.11
B=1.92
+=132.
the other set of 1-5 is not easily obtainable
All lit.

Ok.  It seems that the issue is upstream of the blanking board, as they unblank in certain circumstances.  I was thinking of the fact that you said in reset all of them lit as I went to sleep this morning, and realized that bit of info likely clears the blanking board of guilt in this issue.  I'll take a look at my schematics and take some measurements on mine later after work.

-Pat

[Cubdriver]

Oh, and don't worry too much about the +175V supply reading 132V - I just looked at the schematics for the power supply wondering if you might be a bad filter cap in that circuit too (there isn't one), and found a note adjacent to the output. 

Note 4 - "THE +175V POWER SUPPLY WILL READ APPROX. 135V rms ON MANY VOLTMETERS DUE TO ITS HIGH RIPPLE"

Sounds like that at least is pretty much right where it should be.   

-Pat

[TheSteve]

I can confirm the Nixie supply voltage is fine. I believe the ripple is good for the tubes and done on purpose.

[neo]

Oh, and don't worry too much about the +175V supply reading 132V - I just looked at the schematics for the power supply wondering if you might be a bad filter cap in that circuit too (there isn't one), and found a note adjacent to the output. 

Note 4 - "THE +175V POWER SUPPLY WILL READ APPROX. 135V rms ON MANY VOLTMETERS DUE TO ITS HIGH RIPPLE"

Sounds like that at least is pretty much right where it should be.   

-Pat

I figured it was but at this point i was running down all possible suspects. So whats the current theory of problem?

[neo]

Also, in 10-18GHZ mode , it is only three digits but it does read the frequency i put on it which unless im wrong proves that the non replaceable stuff is functional.

[TheSteve]

Also, in 10-18GHZ mode , it is only three digits but it does read the frequency i put on it which unless im wrong proves that the non replaceable stuff is functional.

You're inputting a frequency over 260 MHz or so to test this right?

[neo]

Also, in 10-18GHZ mode , it is only three digits but it does read the frequency i put on it which unless im wrong proves that the non replaceable stuff is functional.

You're inputting a frequency over 260 MHz or so to test this right?

Not yet but doesn't the 10Hz- 18GHz mode uses the same circuitry as higher frequencies?

[Cubdriver]

Which input are you using - the Hi-Z BNC on the left, or the N connector on the right?  The 1 megohm BNC input on the left bypasses a lot of the internal circuitry used for the high frequencies.

-Pat

[Cubdriver]

Nevermind - 10Hz-18GHz means you must be using the 50 ohm N connector input.  D'oh!

-Pat

[TheSteve]

I am under the impression the sampler can be dead and the counter will still work to 250/260 MHz or so. I believe the only way to know for certain is to feed a frequency above that range in.

[neo]

I am under the impression the sampler can be dead and the counter will still work to 250/260 MHz or so. I believe the only way to know for certain is to feed a frequency above that range in.

I guess i will have to see if my 608C works.
Anyone got a clue about the 3 digit problem? If it ain't the blanking part then i am completely lost.

[Cubdriver]

Anyone got a clue about the 3 digit problem? If it ain't the blanking part then i am completely lost.

My guess is something in the blanking control circuit, but I haven't had a chance to dig into it yet.

-Pat

[neo]

Very few things are capable of genuinely surprising me but i have to admit, i am genuinely shocked. I got this HP 608c signal generator free at last years hamfest and i never got around to test it just simply because i didn't need frequencies that high. I plug it in for the second time in a year and turn it on, and the thing works perfectly except for the DBM and modulation percent meters. It is even accurate to its frequency gauge. 
Definitely not bad for something that had a tag that said, "Non-functional, please haul away."
It will allow me to test the high end of this 5340A but i have another adapted coming so it will be a couple days.

P.S. Anyone know where i can get a knob for the frequency control shaft? I can't use anything i got because its a big shaft. I found one on ebay but it is 40 bucks just for  a knob.

[neo]

At resolution of 100k in check mode

1=4.52
2=4.42
3=4.42
4=3.82
5=3.89
B=1.94
+=132.
the other set of 1-5 is not easily obtainable
Only the three not affected by blanking lit.

UHF mode

1=0.10
2=0.10
3=0.10
4=0.12
5=0.11
B=1.92
+=132.
the other set of 1-5 is not easily obtainable
All lit.

OK a thought, if low the tubes light, i de-soldered a wire and tied that one point low and the tube lit BUT even with the tube lit it did not display properly.

[neo]

After a couple days digging around in the schematic two things are the result,
1)
2) I know it can work but as near as i can tell it just doesn't want to use more then 3 digits for whatever reason, the blanking circuitry was suspect but near as i can tell it is ruled out because even if bypassed the it will not display anything other than 3 useful numbers all else being 0s.
There has to be a reason for the absence of useful numbers above 3, the fact that it is only the 3 not affected by blanking annoys me, though i don't think i a smart enough to find it. 

[EPTech]

Be careful when paralleling large filter capacitors over existing capacitors for testing. You may exceed the forward peak current capacity of the rectifier diodes, potentially degrading or destroying them. In these older devices they are usually over-specified, so I guess you are OK, but still, be mindful. Sounds like you are on the right way. I agree with my colleagues, recap the entire power supply and look for leaky (warm) tantalum capacitors as well.

Happy repairing.

[neo]

Be careful when paralleling large filter capacitors over existing capacitors for testing. You may exceed the forward peak current capacity of the rectifier diodes, potentially degrading or destroying them. In these older devices they are usually over-specified, so I guess you are OK, but still, be mindful. Sounds like you are on the right way. I agree with my colleagues, recap the entire power supply and look for leaky (warm) tantalum capacitors as well.

Happy repairing.

As of current the problem is so obscure i have no clue where to even look.

[Cubdriver]

My extender card is presently still lost in the black hole that is the Philly Postal facility, so I haven't looked further at it.  Will maybe peruse the manual tonight to see if I can gain any insight into what might be ailing yours.

-Pat

[bitseeker]

Ah, so I this is what got lost in Philly. Well, that's a bummer. I just got caught up on the thread.

[neo]

My extender card is presently still lost in the black hole that is the Philly Postal facility, so I haven't looked further at it.  Will maybe peruse the manual tonight to see if I can gain any insight into what might be ailing yours.

-Pat

Sorry to hear about the mail system getting screwed up.
I had a couple of theories and using one of them i did manage to bypass the blanking but in doing so i disproved all my other theories.
They blank the left 5 digits because they are zeroes, there is nothing reaching the display past the first 3 digits.
I thought to myself, hmm maybe they blank the counter chips?
Nope no connection to the any chip inputs, only outputs and with that i stopped thinking before i broke something.   

[TheSteve]

When you move the resolution slider does the decimal place move?

[neo]

.000KHz
0.00KHz
00.0Khz
.000MHz


That is what it does exactly, so in short yes.

[TheSteve]

Well at least that is working. Just as an FYI when you switch between resolutions(with no input) you can expect all of the digits to light up briefly before the blanking circuit disables all but the right most 3 digits.

The more we determine works/doesn't work the easier it should become narrow down the fault.