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 Post subject: Replacement Meter for a Hickok 605A
PostPosted: Feb Mon 11, 2019 7:15 pm 
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Joined: Apr Wed 22, 2009 6:01 am
Posts: 107
Location: New York City
So the meter on my 605a is completely dead. I think it's open. Just wondering if anyone knows a source for replacements? If not, does anyone have any experience with making a substitute work? It's a fine tester and I hate to leave it languishing if I can find a way to get it going again. All suggestions gratefully accepted!


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Feb Mon 11, 2019 8:58 pm 
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Joined: Jan Thu 24, 2019 1:22 pm
Posts: 47
Location: Centennial, Colorado 80122
The 605A meter is electrically different than the 600A, since it has the multimeter functions.

605A 50uA and 5000 ohms If I remember correctly its the same as for the 534A

600A 500uA and 233 ohms

Unless you can find a used one on the bay your only hope would be Roger Kennedy and it will cost around $200.
Good luck, Bill


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Feb Mon 11, 2019 10:30 pm 
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Joined: Apr Wed 22, 2009 6:01 am
Posts: 107
Location: New York City
Thanks for the reply Bill. I appreciate the response. I'd be happy to pay to replace the meter but I understand Roger is no longer trading.

Thank you for the specs on the 605a meter.


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Feb Mon 11, 2019 10:53 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 18300
Location: Albuquerque, NM 87123
Many of those meters can be repaired. I would open it up to see why it failed.


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Feb Tue 12, 2019 12:05 am 
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Joined: Nov Wed 30, 2016 7:35 pm
Posts: 3434
Location: Sunbury, Ohio 43074
Roger Kennedy is still there I believe. I had some correspondence with him a few months ago. He's buried in work of course, but if you are patient it might be worth an Email.

That said, if you can find a meter with the same or better sensitivity, and the same physical dimensions, you might be able to transplant your meter face into a new meter, and shunt it accordingly. Fussy, but it can be done.

Or it may be that it can be fixed. By "dead" ... you mean as in electrically open? Or broken? Or sticky? I hope you didn't slap an ohmmeter across it to measure it without using a current limit resistor, or it may be most certainly fried by now. But if not, it may still be recoverable.

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www.bbtvtestequipment.com


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Feb Tue 12, 2019 2:16 am 
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Joined: Apr Wed 22, 2009 6:01 am
Posts: 107
Location: New York City
I checked the meter with a battery and resistor in series. No movement at all, which is why I'm surmising the movement is open. I gather this is not particularly unusual for these meters.

Nevertheless it did catch me by surprise. I had not used the tester for about a year. It was fine when I put it away but failed to function when trying to test some tubes. When I tried the battery 1.5v an resistor combo I didn't get any movement as stated above. I guess it must have gone open when it was in storage. :cry:

I was hoping there would be another movement, perhaps by Simpson, that could be adapted to work....

I've sent an email to Roger. Hopefully he's still in business and I'll get a reply. Will let you know if I hear back.

Thanks!

Angelos


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Feb Tue 12, 2019 2:26 am 
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Joined: Nov Wed 30, 2016 7:35 pm
Posts: 3434
Location: Sunbury, Ohio 43074
You might just have an open resistor inside, or depending on how the coil is connected, bad connections or contact with a moving element. Might be able to open up that meter and see whazzup.

What voltage battery and what value resistor did you use?

Either way, if you can't find an exact replacement, there are ways to make a more sensitive meter work (just needs to be shunted properly)...but unless you want to re-engineer the dial scale, you'd have to find one that is both more sensitive, and physically able to accept your existing meter face.

Fussy and bizzywork, but it can be done

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Preserving the history of electronics, one boat anchor at a time! :)
www.bbtvtestequipment.com


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Feb Tue 12, 2019 2:50 am 
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Joined: Apr Wed 22, 2009 6:01 am
Posts: 107
Location: New York City
It was a while ago but, from memory, I used a 1.5 volt battery and I think it was a 2.2k resistor. I certainly hope it wasn’t my own foolishness that damaged the meter! M

I admit fitting the dial the dial scale to a replacement movement seems to me to represent the most challenging part of this repair.

I plan to call Simpsons to see if their technical department can steer me towards an appropriate substitute movememt. The alternative can only be to part out the tester and I really want to avoid that, even if that means investing in new movement.


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Feb Tue 12, 2019 2:55 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 12338
Location: Mpls, Minnesota
Some have an internal wirewound resistor which will corrode and open as has been mentioned. Sometimes continuity is lost in the spiral spring adjustments on the front and back of the meter, try exercising them a few times and see if it helps. Remember to return then to the original position.

Dave


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Feb Tue 12, 2019 7:42 am 
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Joined: Nov Wed 30, 2016 7:35 pm
Posts: 3434
Location: Sunbury, Ohio 43074
Assuming a 5K ohm meter resistance, a 1.2K series resistance, and a 1.5V battery, this "should" have sourced .00024A or 24 microamps if my math is correct at this hour. Ohms law states I=V/R, or 1.5/total resistance which in this case is 5K + 1.2K. We're assuming that the 5K stated by Bill Eccher is correct. If so, then:

the 605A meter is a 50uA sensitivity unit, this test setup should have resulted in approximately half scale deflection.

However, if it's a 500uA sensitivity unit, this particular test setup would not have moved the needle enough to be seen most likely.

If it happens to be a 500uA movement at 233 ohms, then the test setup would have yielded a current of 86 microamps. So it's importrant ot know what the meter resistance is supposed to be.

You could try substituting a 1k potentiometer for your 1.2K fixed resistor. I'd still use perhaps a series 470 ohm as a limit should you accidentally turn the pot all the way to the minimum end.

Someone check my math ... it's 2am :)

_________________
Preserving the history of electronics, one boat anchor at a time! :)
www.bbtvtestequipment.com


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Feb Tue 12, 2019 8:47 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 12338
Location: Mpls, Minnesota
Schematic and my meter list states a 50uA and 5000 ohms for the 605A

Dave


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Feb Thu 14, 2019 10:13 am 
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Joined: Apr Wed 22, 2009 6:01 am
Posts: 107
Location: New York City
Just a quick update. I reached out to Roger Kennedy, as per Bill's suggestion. Roger replied quite quickly and quoted a replacement meter price of $195.75. I decided to go ahead and order one. Hopefully it will arrive in a reasonable amount of time and will do the job. Unfortunately, the new meter apparently has different dimensions so I'll have to modify the tester's face plate, assuming I can't just make a spacer to fit. It might be ugly but I'd rather not cut into the instrument if I can avoid it.

In the meantime I'll also try repairing the original meter this weekend as per Barry and easyrider8's suggestions. Will report back on progress, or lack thereof....

Thanks for the help and advice guys!

Angelos


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Mar Fri 08, 2019 3:09 pm 
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Joined: Apr Wed 22, 2009 6:01 am
Posts: 107
Location: New York City
Just a quick update. The original meter is definitely open circuit. Unfortunately the break seems to be internal and not near the coil ends. I've ordered a new one from Roger Kennedy. 4- 5 weeks to supply.

Angelos


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 Post subject: Re: Replacement Meter for a Hickok 605A
PostPosted: Mar Fri 08, 2019 3:39 pm 
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Joined: Nov Wed 30, 2016 7:35 pm
Posts: 3434
Location: Sunbury, Ohio 43074
Keep the old one. Perhaps someone can repair it eventually and you can have a spare or sell it or otherwise keep it out of the landfill.

The new one should fit without too much surgery I'd think... Roger Kennedy has been in business for a long while and knows what it takes to replace a meter.

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Preserving the history of electronics, one boat anchor at a time! :)
www.bbtvtestequipment.com


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