[Heathkit] Update - Testing the SB-401's 6AV11 on the Eico 666 tester

[jack m]

Thanks to all who replied to my query.  Here is a helpful update documenting my experience and findings for anyone who can use the information:
 
I set up the Eico 666 using the 6D10 triple triode pin specs and the 6AV11 voltage settings as provided in the Coletronics charts.  All three triodes tested out with approximately the same readings on all 4 NOS 6AV11 tubes.  I then tested a known defective 6AV11 with a bad 3rd triode section, and it tested bad using the 6C10 pin setup as per the chart. 
 
Meanwhile, I think I decoded the pinout and mickey mouse setup schemes using the Coletronics/Eico compactron adapter (you set up a 12-pin compactron tube using a "moving key" pin number for each section, where the adapter's 12-pin compactron socket has been drilled with a "13th hole" ("0" key position), and you move the tube around to two additional pin number "keys" to match the changed switch selections for each of the remaining two triode sections.  The 666 setup info for the 6D10 used 3 "keys", while the 6AV11 setup used only two, but with switch changes as per the Coletronics data.  Meanwhile, the only difference between 12BQ and 12BY basing diagrams appears to be the internal shield connection off pin #8, which is not used in any test sequence.  The 666 tester has a 9-pin capacity with the plate cap as a tenth "pin", and an actual plate cap on the adapter for that connection  (the "mickey mouse" claim made earlier.)
 
As it turned out, and after "decoding" the scheme using the 6D10 setup as a reference, there was a mistake on the 6AV11 tube setup.  I corrected the errant number, and the 6AV11 tested properly.  This was kind of embarrassing.
 
At least, the Heath TT-1A uses a second 9-pin miniature plug with the octal plug for a total of 17 pin capacity plus the plate and grid caps, or a total of 19 potential selections to enable their compactron and other newer adapters, but all selections are made using the selector knobs rather than rotating the tube and as three additional setup numbers on each tube lineup.
 
I am always on the lookout for a second TT-1A at a reasonable price, so y'all may eventually find my Eico 666 tester on eBay sometime in the next few years.  The TT-1A's are pricey - around $300-$400 when they come up, and you best not care about condition of the outer material-covered case! 
 
Regards,
 
Jack  W3RU
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 24 Jun 2014 15:52:24 +0000
> From: jack m <oldvette at hotmail.com>
> To: "heathkit at mailman.qth.net" <heathkit at mailman.qth.net>
> Subject: [Heathkit] Testing the SB-401's 6AV11
> Message-ID: <COL126-W109F4EB40212CC9E70F239DE1E0 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> I have 4 spare NOS/NIB 6AV11 triple triodes for my SB-401's which test perfectly on my TT-1A tube tester.  All 3 triode sections of each tube are within 5% and well over the stated test minimums.
>  
> I've tested the same tubes on my EICO 666 tester using the 610 compactron adapter and the latest published Coletronics test data.  Triodes 1 and 2 test good at 110 to 120 for each of the 4 NOS tubes, but Triode 3 does not read properly on ANY tube - most likely from erroneous tube setup data.  Checking similar tubes with the 12BY basing diagram (the 6K11 and 6Q11 compactrons), these tubes call for entirely different section setups according to the Coletronics data.
>  
> After an hour of freezing my brain and cross-checking with the 1975 RCA tube manual, I thought I would ask if anyone else has run into this situation with the Eico 666, and perhaps learn of a more suitable test setup for the 6AV11.  
>  
> I acquired the 666 to avoid lugging the TT-1A boat anchor between locations for obvious reasons, but would like to have more confidence in it - even though the adapter and compactron pin key change schemes are a real PITA when compared to the TT-1A.
>  
> Thanks for the help!
>  
> Jack  W3RU
>  		 	   		  
> 
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> End of Heathkit Digest, Vol 125, Issue 15
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