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  #31  
Old 09-09-2018, 10:07 PM
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Over the years I've had a recurring bad dream where I come close to damaging the neck on the 21AXP22 in my CTC-5. Hopefully I won't have twice as many dreams now!

I was out of town for a few days but spent this rainy afternoon finishing the electolytics then started going section by section through the BB's. I've completed most of the LV, HV & horizontal. I did a brief filament-only power up with the LV rectifiers removed, just to check for any drama (there was none). I may allow myself a full-power up soon. I did goof one thing up today: while moving the chassis around on the bench I put too much pressure on one of the IF cans and bent it right over, snapping a couple wires inside. I couldn't find one end of one of them at all. The good news: it's a common part and a quick check of my big old coil box turned up 3 or 4 exact replacements in a few minutes. Hopefully the pain of having to deal with touching up the alignment will keep me from being so clumsy next time! It is HEAVY and rather awkward.
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  #32  
Old 09-11-2018, 12:48 PM
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I notice that the fourth photo shows a tag on the chassis: ".75 AMP 250V".

This would be a rarity indeed - a 250V power supply when the only country with a color TV infrastructure was entirely 120V.

Was this built as a demonstration or test set to be used abroad?
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  #33  
Old 09-11-2018, 01:18 PM
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Or perhaps this is just the spec of a fuse in the set?

jr

edit add: Sams shows a 3/4A 250V fuse as "M3", in the 240 Volt supply.

Last edited by jr_tech; 09-11-2018 at 02:51 PM. Reason: add info
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  #34  
Old 09-11-2018, 02:25 PM
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Quote:
Originally Posted by Robert Grant View Post
I notice that the fourth photo shows a tag on the chassis: ".75 AMP 250V".

This would be a rarity indeed - a 250V power supply when the only country with a color TV infrastructure was entirely 120V.

Was this built as a demonstration or test set to be used abroad?
Probably a 120V set with a 250V spec fuse. That could be the B+ voltage for a fused B+ line...Or it could be that Philco recognized the voltage spec of a fuse if of little consequence and it is the current rating of the fuse that matters.
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  #35  
Old 09-11-2018, 10:02 PM
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Funny that fuses would get mentioned-get a load of this:
I tested the fuses and they were all fine, which was encouraging. I did power the set up briefly only to find a light show inside the 5U4-whoops! While studying the schematic I was trying to figure out why no fuses blew. Well...somebody long, long ago (they were covered with a thick layer of dust) replaced 2 of the three with 2 amp fuses and the third with 1.5 amp! Yep, well, think of the cold, hard cash they saved on all those fuses they once had to buy!

I have a handy dandy Sencore "Fuse Safe" circuit tester which clips in place of a fuse & has a meter to test current draw. It's the HV circuit that's causing issues. It took me some digging to figure out which circuit due to some confusion: Sams has the diagram mislabeled on their drawing as to which is which, plus there seem to have been some running changes as to what Philco specified for each one. I'm not the best diagnostician but I'll pluck away at it...if I keep disconnecting stuff I'm bound to figure it out! Oh, one more thing-when I powered up I let a nice puff of smoke (and a sharp bang) out of something. I was quite concerned, but less so after I spotted the culprit. It seems that yours truly, in a boneheaded move, picked up a 10v capacitor and wired it in where a 50v (IIRC) was called for. Poor little thing didn't stand a chance!
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  #36  
Old 09-12-2018, 12:20 AM
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Quote:
Originally Posted by Robert Grant View Post
I notice that the fourth photo shows a tag on the chassis: ".75 AMP 250V".

This would be a rarity indeed - a 250V power supply when the only country with a color TV infrastructure was entirely 120V.

Was this built as a demonstration or test set to be used abroad?
.75 amp 250v fuses are generally used for the horizontal sweep B supply. I do not think it has any reference to the a.c. input.
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  #37  
Old 09-12-2018, 10:34 AM
dieseljeep dieseljeep is offline
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Quote:
Originally Posted by Robert Grant View Post
I notice that the fourth photo shows a tag on the chassis: ".75 AMP 250V".

This would be a rarity indeed - a 250V power supply when the only country with a color TV infrastructure was entirely 120V.

Was this built as a demonstration or test set to be used abroad?
First of all: The set draws a lot a lot more primary current than .75 amp. At the time all low current fuses were rated at 250volts.
Fuses were designed for fault current as well as overcurrent protection. The line fuse, if used is somewhere around 8 amp, 125 volts, 125% of run current.
Fuses have changed drastically over the last 20 or 30 years regarding fault current. All fuses 10 amp and higher in the 3AG size are either porcelain tube or sand filled.
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  #38  
Old 09-18-2018, 01:10 PM
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The thread has been cleaned up. Let's try to keep the discussion limited to Bryan's Philco restoration going forward. The set was sold, the buyer and seller both seem to be happy with the sale, it's done.
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