[TechAssist] fix. Mitsubishi WT42311, ch# VK20 open pico fuse F9A02
- From: Phil Bader <tjanphyl@xxxxxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Tue, 12 Apr 2005 15:48:48 -0400
Replaced both convergence ICs (on convergence/deflection board.): IC8C01
and IC8C02 both STK392-110.
Used very good quality OEMs.
Replaced F9A05 pico 5A on SMPS module.
Checked associated -24V source connected to pico.(D9A61,lytics C9A72,C9A73).
Came up with good display, only slightly out of convergence.Adjustable
thru customer menu.
The way this unit unmates from the case and the whole "chunk" can be put
up on the bench to service, flipped on its side to access trace/pin side
of the STKs, board removal,etc it's very well engineered.
Thumbs up to Mitsubishi.
Phil Bader
Philip Bader
Jan Phyl TV Inc. (estab. 1976)
3420 Recker Hwy. Winter Haven, Fl. 33880
Fax (863) 299-8821
email: tjanphyl@xxxxxxxxxxxxxxx
Leonard Caillouet wrote:
>Could have just blown the fuse. Given the quality of replacement ICs (I
>even had a DOA from Toshiba recently) I might take a shot at just changing
>the fuse.
>
>Leonard G. Caillouet
>Electronics World
>1261 NW 76 Blvd
>Gainesville, FL 32606
>352-332-5608
>352-332-5668 FAX
>
>----- Original Message -----
>From: "Phil Bader" <tjanphyl@xxxxxxxxxxxxxxx>
>To: <techassist@xxxxxxxxxxxxx>
>Sent: Monday, April 11, 2005 4:21 PM
>Subject: [TechAssist] Re: Mitsubishi WT42311, ch# VK20 open pico fuse F9A02
>
>
>I always shoot the breeze with the customer at drop off. I find I get a
>wealth of info as to the circumstamces preceding the failure. He said
>this seemed to happen right after a storm and some other things in the
>home were affected. I'm thinking the STKs were surged. I know this seems
>unlikely, but here in Florida we see a raft of shorted HOT transistors
>each summer with no other explaination. I will install a good pair of
>chips, the 5A pico fuse and hold my breath.
>Thanks,
>Phil Bader
>
>Philip Bader
>Jan Phyl TV Inc. (estab. 1976)
>3420 Recker Hwy. Winter Haven, Fl. 33880
>Fax (863) 299-8821
>email: tjanphyl@xxxxxxxxxxxxxxx
>
>
>
>Leonard Caillouet wrote:
>
>
>
>>Definitely a last resort. If the chips run really hot or there are
>>adjustments at the limit I would try to straighten out the indivisual
>>settings rather than reset. If the centering is way off and you end up
>>
>>
>with
>
>
>>too much dc on the outputs to center it you might have to reset and start
>>over after centering but I have never had to do so.
>>
>>Leonard G. Caillouet
>>Electronics World
>>1261 NW 76 Blvd
>>Gainesville, FL 32606
>>352-332-5608
>>352-332-5668 FAX
>>
>>----- Original Message -----
>>From: "Phil Bader" <tjanphyl@xxxxxxxxxxxxxxx>
>>To: <techassist@xxxxxxxxxxxxx>
>>Sent: Monday, April 11, 2005 1:55 PM
>>Subject: [TechAssist] Re: Mitsubishi WT42311, ch# VK20 open pico fuse F9A02
>>
>>
>>Understood. But, I don't want to do the reset of the converg. eeprom as
>>you described in procedure #1. if it comes up almost perfect without,
>>right? That's the last resort?
>>Phil
>>
>>Philip Bader
>>Jan Phyl TV Inc. (estab. 1976)
>>3420 Recker Hwy. Winter Haven, Fl. 33880
>>Fax (863) 299-8821
>>email: tjanphyl@xxxxxxxxxxxxxxx
>>
>>
>>
>>Leonard Caillouet wrote:
>>
>>
>>
>>
>>
>>>Yes, you likely have a bad convergence output. Make sure you use a good
>>>supplier. Have seen no other problems with these other than bad solder
>>>joints on the outputs and bad ICs.
>>>
>>>Mitsubishi techs have told me that some of the amps blow because they are
>>>over driven and the convergence needs to be reset and redone from scratch.
>>>I have not seen one that appeared to have that problem. If you find that
>>>the convergence is at its limits on any of the adjustments you might need
>>>
>>>
>>>
>>>
>>to
>>
>>
>>
>>
>>>do so, but I would avoid it. Every one that we have done has been fine
>>>
>>>
>>>
>>>
>>with
>>
>>
>>
>>
>>>minor alignment and no repeat failures. The chips do run hot, however.
>>>
>>>1. RESET THE CONVERGENCE EEPROM, PRESS "MENU 2259" TO ENTER THE
>>>
>>>
>CONVERGENCE
>
>
>>>MENU THEN PRESS "8970" TO RESET.
>>>
>>>Leonard G. Caillouet
>>>Electronics World
>>>1261 NW 76 Blvd
>>>Gainesville, FL 32606
>>>352-332-5608
>>>352-332-5668 FAX
>>>----- Original Message -----
>>>From: "Phil Bader" <tjanphyl@xxxxxxxxxxxxxxx>
>>>To: <techassist@xxxxxxxxxxxxx>
>>>Sent: Monday, April 11, 2005 10:10 AM
>>>Subject: [TechAssist] Mitsubishi WT42311, ch# VK20 open pico fuse F9A02
>>>
>>>
>>>This is a compact table top projection set. Cute. Chassis pulls out.
>>>Push power, just a click.
>>>Customer said after a storm (that took out other things in the home)
>>>this set was dead.
>>>On the power supply board I found one pico fuse open: F9A05, a 5 amp
>>>fusing the negative (-) 24 volt source. This supplies negative voltage
>>>to the two convergence IC's IC8C01 and IC8C02, both STK392-110 on
>>>another board.
>>>Nothing else "seems" bad except the fuse. Would you replace the two
>>>converg. STKs as well?
>>>(- )24VDC source runs as follows: smps transformer pin 22 to F9A05, to
>>>diode D9A61, filtered by caps C9A72 and C9A73 both 330uF@35V, and
>>>exiting at edge connector "KF" pin 15,16, coupling the power board to
>>>the deflection board where the STK392-110's live. All the lo-ohm fuses
>>>near STKs are OK, no diodes seem bad.
>>>Phil Bader
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>---------------------------------------------------------------------------
>>
>>
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