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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
Hitachi 27AX3B no power after attempting to fix vertical deflection

 

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jts1957
Veteran


Feb 1, 2018, 8:57 PM

Post #26 of 35 (468 views)
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Re: [NT7000] Hitachi 27AX3B no power after attempting to fix vertical deflection [In reply to] Can't Post

Who knows? Really does not matter. It's not like replacement costs are exorbitant.


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Location: Far, Far Away


NT7000
New User

Feb 1, 2018, 9:04 PM

Post #27 of 35 (466 views)
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Re: [jts1957] Hitachi 27AX3B no power after attempting to fix vertical deflection [In reply to] Can't Post

I'm not worrying about replacement cost... the shipping will likely be more expensive... what I'm saying is there is likely a reason for it to blow out, since these kind of parts rarely throw in the towel for no reason. Then again, I did have a Sony trinitron 20" set that popped it's main fuse one time with no apparent cause. I replaced said fuse, and the set is solid as a rock to this day.


NT7000
New User

Feb 2, 2018, 1:30 AM

Post #28 of 35 (450 views)
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Re: [NT7000] Hitachi 27AX3B no power after attempting to fix vertical deflection [In reply to] Can't Post

Alright, I got the scope probes and hooked up to base of Q710, and this is what I got.


[URL=http://s909.photobucket.com/user/NTkiller7000/media/IMG_0214_zpsjx6oz3bc.jpg.html]

I apologize for the blurry image, but at least it's an image. I only get a split second of this waveform before it disappears, accompanied by a soft click near the FBT. Does this look correct?


jts1957
Veteran


Feb 2, 2018, 2:33 AM

Post #29 of 35 (447 views)
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Re: [NT7000] Hitachi 27AX3B no power after attempting to fix vertical deflection [In reply to] Can't Post

Waveform 19 has same general shape. Photo of theirs, I think shows approx. 750MV p-p Horiz rate (10us).
Yours photo/notes doesn't indicate the Volts/Division or Time/Division settings. One would be speculating Rate and peak-peak without knowing.


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Location: Far, Far Away


NT7000
New User

Feb 2, 2018, 2:38 AM

Post #30 of 35 (445 views)
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Re: [jts1957] Hitachi 27AX3B no power after attempting to fix vertical deflection [In reply to] Can't Post

Sorry, time/div set to 20 uS, volts/div set to 20mV, probe set to 10X. That's everything, right? Not used to using my new "tool" (toySmile) yet. I looked at their image, but I can't make heads or tails of it since it's so blurry. It does appear to be sort of a square wave, so it must be somewhat close. Have any idea why it stops generating the H. drive after a split second?


(This post was edited by NT7000 on Feb 2, 2018, 2:47 AM)


jts1957
Veteran


Feb 2, 2018, 2:52 AM

Post #31 of 35 (443 views)
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Re: [NT7000] Hitachi 27AX3B no power after attempting to fix vertical deflection [In reply to] Can't Post

Assuming 3 vertical divisions, times 20mV/div. = 60mV ... times 10 for probe = 600mV. 20us is H. rate. I'd say close enough for Government work. Set's not staying on. Parts mentioned earlier HAVE been replaced? Is there scan-derived 25V for a moment? Collector voltage on Q953 for a moment?


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Location: Far, Far Away

(This post was edited by jts1957 on Feb 2, 2018, 2:58 AM)


NT7000
New User

Feb 2, 2018, 2:57 AM

Post #32 of 35 (441 views)
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Re: [jts1957] Hitachi 27AX3B no power after attempting to fix vertical deflection [In reply to] Can't Post

Ok, so it's confirmed, we have H. Drive, but only for a split second. Maybe the reason it's cutting out is the jungle IC stops driving it once it realizes none of the other power rails are coming up?


jts1957
Veteran


Feb 2, 2018, 3:00 AM

Post #33 of 35 (439 views)
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Re: [NT7000] Hitachi 27AX3B no power after attempting to fix vertical deflection [In reply to] Can't Post

May want to check those power rails for correct voltage / steady or there for a moment. Or it's being shutdown for cause.


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Location: Far, Far Away

(This post was edited by jts1957 on Feb 2, 2018, 3:03 AM)


NT7000
New User

Feb 2, 2018, 5:00 AM

Post #34 of 35 (435 views)
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Re: [jts1957] Hitachi 27AX3B no power after attempting to fix vertical deflection [In reply to] Can't Post

I checked for power at the jungle IC. Only pin 30 is getting 9V, and for just a second.


NT7000
New User

Feb 6, 2018, 3:51 AM

Post #35 of 35 (389 views)
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Re: [NT7000] Hitachi 27AX3B no power after attempting to fix vertical deflection [In reply to] Can't Post

Well, I have a new symptom: it's now blowing mains fuses.
MadGRRRR!!!Mad
I'm tempted to buy an arcade chassis, build a case, and turn this noise into a standalone arcade monitor. The only problem is, I'm not 100% sure this tube is any good! It's a Hitachi a68ksa30x, which saw service in arcade monitors. But I haven't had it on long enough to see if there is anything wrong with it.

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