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DougButtimer
Joined: 13 Jul 2008
Posts: 2
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 Posted: Sun Jul 13, 2008 7:28 pm Post subject: TV picture fades until it disappears - doesn't store tuning |
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| I am attempting to repair a Toshiba 14N21B2 which has been given to me. It is not currently tuned, and although it goes through the automatic tuning process and finds unsync'd channels, nothing is remembered and eventually within about 5 mins) the "picture" fades away. I originally suspected a power supply fault, but can't find any outputs that "fade" in the same way. I don't have a circuit diagram, but there is one 56 pin DIL package which I also can't find any datasheet for. - It is an ST part and has the following markings " MBI195C70BF012B P220F0414". It also has "Orion" stamped on the package so I wonder if it is a custom part. Anybody got any information or advice ?? Many thanks ! |
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| Posted: Mon Jul 14, 2008 3:30 am Post subject: |
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Just replace the "N" chip failing that replace the whole tv set and the stand.Fault could possibly be in the small battery that holds the memory located inside the cct board.I had the same problem with this model.Tuning drifted off course.I think the tv is in landfill somewhere.I couldn't fix the freakin thing so I donated it to the local council.But I could not get a cct diag either.Say, is that the one in the silver/grey case isnt it?
With buttons on top. The wiring is so birdnesty its hard to fix.Overall its a good tv.Start by tuning the lowest band as it drifts you can see each tv channel in turn or leave it in tune mode then it stays on that channel.I know how to make it whistle. Drop it from a very high building.Are you gonna sell it?Is your name really Moe or Curly?Its a capacitor (condensor for the oldies).If you see smoke come out of it try to get the smoke back and put it into the component it came out of.Sounds like a capacitor or voltage problem we should get free cct diags!!!!!!!!!!!!!!!!!!!!!!!!! |
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| Posted: Mon Jul 14, 2008 3:32 am Post subject: |
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| send an email to the orion galaxy you should get a reply in 34560000 light years. they make that chip there |
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vtech
Joined: 08 May 2006
Posts: 1264
Location: USA
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| Posted: Mon Jul 14, 2008 4:13 am Post subject: Re: TV picture fades until it disappears - doesn't store tun |
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| DougButtimer wrote: | | I am attempting to repair a Toshiba 14N21B2 which has been given to me. It is not currently tuned, and although it goes through the automatic tuning process and finds unsync'd channels, nothing is remembered and eventually within about 5 mins) the "picture" fades away. I originally suspected a power supply fault, but can't find any outputs that "fade" in the same way. I don't have a circuit diagram, but there is one 56 pin DIL package which I also can't find any datasheet for. - It is an ST part and has the following markings " MBI195C70BF012B P220F0414". It also has "Orion" stamped on the package so I wonder if it is a custom part. Anybody got any information or advice ?? Many thanks ! |
I don't have the manual but I think the ST chip is actually one of their IC2bus STVxx series;
http://www.datasheetcatalog.org/datasheet2/7/0ysy4edza4487xe81z3oap9s7icy.pdf
There is an "elegant copy" of 14N21ES posted here which may be similar to your set?
http://www.eserviceinfo.com/downloadsm/15560/Toshiba_14N21ES.html
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DougButtimer
Joined: 13 Jul 2008
Posts: 2
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| Posted: Mon Jul 14, 2008 7:47 am Post subject: Re: TV picture fades until it disappears - doesn't store tun |
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| vtech wrote: | | DougButtimer wrote: | | I am attempting to repair a Toshiba 14N21B2 which has been given to me. It is not currently tuned, and although it goes through the automatic tuning process and finds unsync'd channels, nothing is remembered and eventually within about 5 mins) the "picture" fades away. I originally suspected a power supply fault, but can't find any outputs that "fade" in the same way. I don't have a circuit diagram, but there is one 56 pin DIL package which I also can't find any datasheet for. - It is an ST part and has the following markings " MBI195C70BF012B P220F0414". It also has "Orion" stamped on the package so I wonder if it is a custom part. Anybody got any information or advice ?? Many thanks ! |
I don't have the manual but I think the ST chip is actually one of their IC2bus STVxx series;
http://www.datasheetcatalog.org/datasheet2/7/0ysy4edza4487xe81z3oap9s7icy.pdf
There is an "elegant copy" of 14N21ES posted here which may be similar to your set?
http://www.eserviceinfo.com/downloadsm/15560/Toshiba_14N21ES.html |
Hi vtech !
Many thanks for the reply. Yes, I discovered the chroma chip in a tin can and it IS one of the IC2bus STV series. I see what you mean about the 14N21ES being an "elegant" manual ! (I may have trouble concentrating on the circuit  )
Certainly having the circuit of a close relation to the 14N21B2 should help progress !
Many thanks again ! |
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vtech
Joined: 08 May 2006
Posts: 1264
Location: USA
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| Posted: Mon Jul 14, 2008 3:45 pm Post subject: Re: TV picture fades until it disappears - doesn't store tun |
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| DougButtimer wrote: | | vtech wrote: | | DougButtimer wrote: | | I am attempting to repair a Toshiba 14N21B2 which has been given to me. It is not currently tuned, and although it goes through the automatic tuning process and finds unsync'd channels, nothing is remembered and eventually within about 5 mins) the "picture" fades away. I originally suspected a power supply fault, but can't find any outputs that "fade" in the same way. I don't have a circuit diagram, but there is one 56 pin DIL package which I also can't find any datasheet for. - It is an ST part and has the following markings " MBI195C70BF012B P220F0414". It also has "Orion" stamped on the package so I wonder if it is a custom part. Anybody got any information or advice ?? Many thanks ! |
I don't have the manual but I think the ST chip is actually one of their IC2bus STVxx series;
http://www.datasheetcatalog.org/datasheet2/7/0ysy4edza4487xe81z3oap9s7icy.pdf
There is an "elegant copy" of 14N21ES posted here which may be similar to your set?
http://www.eserviceinfo.com/downloadsm/15560/Toshiba_14N21ES.html |
Hi vtech !
Many thanks for the reply. Yes, I discovered the chroma chip in a tin can and it IS one of the IC2bus STV series. I see what you mean about the 14N21ES being an "elegant" manual ! (I may have trouble concentrating on the circuit )
Certainly having the circuit of a close relation to the 14N21B2 should help progress !
Many thanks again ! |
...yeh I know, trying to concentrate on the circuit was not easy in THAT Toshiba schematic. 
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