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 Post subject: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Wed 11, 2017 7:52 pm 
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Joined: Sep Wed 30, 2009 4:15 am
Posts: 7
Location: redwood city, calif 94061
does anyone know the real difference between the two? going to augment either with a 667 checker but trying to see which of the 2 military checkers out weigh the other and why,
cheers and 73sw to you all

PS will be firing up my 40mtr (160-40) WS-19 Canadian soon, on a wire antenna, sure would like to know if any of you folks want to try for a contact in a month or so.ciao


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Wed 11, 2017 8:42 pm 
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Joined: Feb Thu 13, 2014 4:57 pm
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Location: Burnaby, BC, Canada
The main difference between I-177 and the TV7 is that the latter doesn't have any 9 Pin (or above) sockets, so you must get a hard-to-find adapter to test newer tubes like the 12AX7.


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Wed 11, 2017 11:15 pm 
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Joined: Sep Wed 30, 2009 4:15 am
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Location: redwood city, calif 94061
wow thank you i have been offered a i-177 and the mx-949 adapter for 150 think ill jump on it


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Thu 12, 2017 12:15 am 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Tucson AZ
I'd jump FAST on that deal!


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Thu 12, 2017 1:15 am 
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Joined: Jan Thu 01, 1970 1:00 am
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One of the main differences is the grid drive signal. The 177 only has a fixed 5 volt signal, the TV-7 has a 5v as well as 1v and .5 v settings. This is important in testing the newer 7 and 9 pin tubes.


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Thu 12, 2017 4:04 pm 
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Joined: Jan Mon 28, 2013 9:35 pm
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Location: Santa Rosa, CA
I've had and used both (I-177, MX-949 and TV-7's).
The TV-7 is better built and will test more tubes.
Steve


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Sun 15, 2017 1:27 am 
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Having owned and repaired and calibrated both I can't agree that the build quality on the 177 is not as good as a TV-7. Different companies were contracted to build units to the gov't specs, my 177/B was built by Simpson, been using it for about 30 yrs. I have a TV/2B/U that was built by the JH Keeney Co. whoever that was but is top quality.


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Sun 15, 2017 10:25 pm 
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Location: Lincoln City, OR
Greetings to the Forum:

pelud writes:

Quote:
The main difference between I-177 and the TV7 is that the latter doesn't have any 9 Pin (or above) sockets, so you must get a hard-to-find adapter to test newer tubes like the 12AX7.


Is it possible that you have this backwards (meant "former" rather than "latter")? My TV-7 B/U has sockets for both 7 and 9 pin miniature tubes.

Regards,

_________________
Jim T.
KB6GM


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Thu 19, 2017 8:58 am 
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Location: Burnaby, BC, Canada
Yes, you are completely right. I meant to say former.

I guess as the saying goes, I'm not lysdexic and I believe in dog.

Jthorusen wrote:
Greetings to the Forum:

pelud writes:

Quote:
The main difference between I-177 and the TV7 is that the latter doesn't have any 9 Pin (or above) sockets, so you must get a hard-to-find adapter to test newer tubes like the 12AX7.


Is it possible that you have this backwards (meant "former" rather than "latter")? My TV-7 B/U has sockets for both 7 and 9 pin miniature tubes.

Regards,


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Sat 21, 2017 1:52 am 
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Location: Dayton Ohio
As mentioned, the I-177 is great for preWWII big tubes (octal and older) but are very hard on newer miniature, pushing them past their limits.

-Steve

_________________
Radio Interests
-Zenith
-Sparton
-Pre-War FM
Consoles and floor models, the bigger, the better!


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Sat 21, 2017 5:26 am 
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You'll need the (rare and quite expensive) MX-949 extension/adapter to test miniature noval (B9A) tubes and the patching/unpatching method needed is slow, tedious and error prone. For exemple, checking both sections of a 12A*7 series dual triode is a long process and what only takes a couple of seconds on a TV-7 needs a few minutes on the I-177/MX-949 combo. I had these and quickly sold them without regrets. One of the most inconvenient tube tester I ever had. There are many more user-friendly and accurate tube testers available than the I-177. Only good for antique radio tubes and if you can get it really cheap (40 to 60$ without the adaptor).


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Sat 21, 2017 6:51 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Tucson AZ
The mx-949 isn't that rare, but they can be pricey. Not too difficult to make one for yourself if you wanted too. I did.

I've never found using the MX-949 so slow and tedious. Yeah, it might take a little longer to test some tubes, but when was the last time the end of the world hinged on the speed of how fast a tube was tested?

If you can find a decent shape I-177 for 40-60, then buy it for sure because that auction site shows market value of the 177 to be higher than that, contrary to anyone with the opinion of 40-60.


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Sat 21, 2017 7:14 pm 
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Joined: Jan Mon 18, 2010 2:13 am
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Location: Dayton Ohio
I found this Espey model 105 which from what I can figure out is the same as an I-177.

Definitely a keeper!

-Steve


Attachments:
espey105.jpg
espey105.jpg [ 88.81 KiB | Viewed 620 times ]

_________________
Radio Interests
-Zenith
-Sparton
-Pre-War FM
Consoles and floor models, the bigger, the better!
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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Sat 21, 2017 7:18 pm 
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Location: Tucson AZ
That's freakin neat!


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Sat 21, 2017 9:30 pm 
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Location: Latham NY
Sure looks like it's the same, never seen one of these.


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Tue 24, 2017 3:20 am 
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xwarp wrote:
The mx-949 isn't that rare, but they can be pricey. Not too difficult to make one for yourself if you wanted too. I did.

I've never found using the MX-949 so slow and tedious. Yeah, it might take a little longer to test some tubes, but when was the last time the end of the world hinged on the speed of how fast a tube was tested?

If you can find a decent shape I-177 for 40-60, then buy it for sure because that auction site shows market value of the 177 to be higher than that, contrary to anyone with the opinion of 40-60.


When using test equipment, speed of setting and convenience of use are important features in most situations. For instance I frequently need to compare the two sections of a dual triode like a 12AX7 or 12AU7 to find a good balanced tube. On my Hickok 534B this only requires moving four rotary switches from 2-1-0-3 to 7-6-0-8 (about 4 seconds). Now try this with your I-177/MX949 combo and all his jumpers and get back with your (best) results. And now, suppose you have a hundred tubes to test... you'll quickly learn the real meaning of the word tedious.

Let me quote the late Alan Douglas from his (excellent) book "Tube Testers and Classic Electronic Test Gear" regarding the I-177 (p.63):

... For instance the 6SN7 gets a proper test on only one section, while the other is run with no grid bias. The I-177 will test a few 7-pin miniatures, but has no 9-pin sockets. Later tubes were handled with an outboard adapter MX-949, with connections set up by jumper cords. This is very tedious, and considering the scaricity and high price of the MX-949, the I-177 is best used only for antique tubes, in conjunction with a "modern" tester...

I think there's no doubt here that Alan really knew a lot about tube testers...


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 Post subject: Re: I-177 compared to a TV-7b,d,/u plus
PostPosted: Jan Wed 25, 2017 10:46 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1001
Location: Tucson AZ
Alan made a statement based on his opinion. Nothing wrong with what he wrote, but, his opinion is his own.

I would agree that it would be tedious if all I was doing was comparing different 9 pin tubes all day.

I don't, so the few extra minutes to do the job is no big deal.


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