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How did I do? (EICO 625 Vacuum Tube Tester)
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Author:  booangler [ 04 Nov 2008, 16:31 ]
Post subject:  Re: How did I do? (EICO 625 Vacuum Tube Tester)

Gio,

My cheap DVM will not measure VAC that low. So, I ordered a second meter last night. As soon as I know more I will follow-up.

Alan

Author:  Gio [ 04 Nov 2008, 19:45 ]
Post subject:  Re: How did I do? (EICO 625 Vacuum Tube Tester)

Are you sure it is the meter? It could be that there is no voltage there to measure.

Author:  booangler [ 04 Nov 2008, 19:59 ]
Post subject:  Re: How did I do? (EICO 625 Vacuum Tube Tester)

Gio,

99% sure it is the meter. I tried to get a reading from my 6EU7, that test out as good, but my meter recorded nothing. Nothing even though I could see the heaters glowing. So, it the meter.

Alan

Author:  booangler [ 11 Nov 2008, 15:35 ]
Post subject:  Re: How did I do? (EICO 625 Vacuum Tube Tester)

Latest update - new meter same results no voltage showing!!!! WTF ---- that is until I took the damn thing apart. I found a ball of fur, hair, dust and other unidentifiable stuff piled up around switch 1 and 2. I also noticed some crap in the socket and removed that. I put it all back together and the heaters fired up immediately for the 6BQ5. What a pisser. Top it off I paid a guy 30 bucks to look the unit over and make sure it was working properly. My guess is he just took my money and said he checked it. I'll have to pay him a visit. Funny I thought he was trust worthy. Wrong again.

My other error is a bit more embarrassing. When I was testing the 6eu7 i could see the heaters going on but I was not getting a reading on my meter. Seems that my dyslexia got me. When looking at the tube data sheets I forgot to reorient my self when looking down at the socket. Instead of checking pin 1 and 2 I was checking pin 8 and 9. Queue the Homer sounds - Doh!!!

So, here is my next big question. Since the scum bag metioned above did not really check the unit out, should I just go ahead and replace all the old resistors, caps and the one tube (CKR-6H6)? Or, should I check with my future professors at RIT, I know one is a guitarist and works on his own amps, for a reference to a decent repair center?

Any and all thoughts appreciated.

Thanks all and remember "dyslexics of the world untie."

Alan

Author:  Gio [ 11 Nov 2008, 21:13 ]
Post subject:  Re: How did I do? (EICO 625 Vacuum Tube Tester)

Hi Alan, good to hear you got it going.

I would not bother with the resistors, they are generally ok. Check the capacitors for leaks, leaky caps should be replaced right away. It may be worthwhile to replace all the old electrolytic types.

Cheers

Author:  booangler [ 11 Nov 2008, 21:16 ]
Post subject:  Re: How did I do? (EICO 625 Vacuum Tube Tester)

booangler wrote:
Thanks all and remember "dyslexics of the world untie."

Or is that Unite, I always get that backwards! ;)

Author:  iroquoisny [ 02 Jan 2009, 10:00 ]
Post subject:  EICO 625 Vacuum Tube Tester - Upgrades

Helpful hint based on recent experience with my EICO 625 vacuum tube tester after many years of non-use: Short light was on almost all the time when testing. Changing the old 0.01 mFd paper cap to a newer cap with 600V working limit solved that problem. Meter was reading low on known good tubes in select position 2. The 510ohm 5% resistor when measured was over 1Kohm, which based on ohms law probably cut the current in half and resulted in a low meter reading. I've ordered a replacement resistor which I believe will solve that problem. You might want to check all precision resistor values (allowing for the tolerance stated on the schematic) to make sure your unit will generate merit readings that are reasonably accurate.

Author:  booangler [ 02 Jan 2009, 10:08 ]
Post subject:  Re: EICO 625 Vacuum Tube Tester - Upgrades

iroquoisny wrote:
Helpful hint based on recent experience with my EICO 625 after many years of non-use: Short light was on almost all the time when testing. Changing the old 0.01 mFd paper cap to a newer cap with 600V working limit solved that problem. Meter was reading low on known good tubes in select position 2. The 510ohm 5% resistor when measured was over 1Kohm, which based on ohms law probably cut the current in half and resulted in a low meter reading. I've ordered a replacement resistor which I believe will solve that problem. You might want to check all precision resistor values (allowing for the tolerance stated on the schematic) to make sure your unit will generate merit readings that are reasonably accurate.

Iroquoisny,

Welcome to the forum.

I did change out the paper cap just to be safe. Haven't really had the need to use the 625 recently so it has been sitting. Radiodaze.com recently moved back to Mendon and has a tester in their shop for public use. I am going to stop over with a couple of tubes to check. Then come back home and compare. From there I will decide what the next step should be. My unit hums like crazy, does yours?

Happy New Year,

Alan

Author:  iroquoisny [ 14 Jan 2009, 15:40 ]
Post subject:  Re: How did I do? (EICO 625 Vacuum Tube Tester)

Hey Alan, Looks like you may also be a local somewhere in the Rochester area. I sent an email in to Radio Daze to confirm a walk-in tube test availability, and they said, "yes, come on down". :P Do you remember what type/model tester they have?

I have to wait for resistor deliveries, as it turns out many of them in the metering circuit have shifted out of tolerance over the years. I've also found some other components that don't match the schematic (e.g. the paper -.01 cap was a 0.047...shouldn't make a big difference on that one, another was supposed to be a 500Kohm but measured over a megohm, etc). I also ordered some of those big rubber grommets the chart and panel lights are secured with. Mine have shrunk with age and the bulb and holders just fall out with no friction fit anymore.

Do you have any clue what the underscore designators are for in the test chart setup settings? I believe the closed parenthesis around some of the levers mean that all those levers should be moved in tandem for merit testing.

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