Kaypro-II Crt to repair

Enrico lazzerini

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Oct 22, 2011, 5:42:10 PM10/22/11

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The computer-Kaypro II had a 9" green phosphor monochrome monitor composed
of a LR30477 E39164 TOSHIBA CRT and a printed circuit steering Toshiba
TLC-134-TV-0. I tried to supply it with 12Vdc and I noticed that the
cathode of the CRT is lit, while the screen does not turns on and no shows
light even using the knob back adjustment for the light intensity.
Wishing to do TV repair technician I need the wiring diagram of the circuit
electric drive Toshiba TLC-134-T-V-0. Is there someone who has it?

Here some pictures:
http://elazzerini.interfree.it/Kaypro-II/Foto2026.html
http://elazzerini.interfree.it/Kaypro-II/Foto2018.html
http://elazzerini.interfree.it/Kaypro-II/Foto2019.html

Thanks in advance for any support.
Enrico

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Curtis McCain

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Oct 23, 2011, 3:06:10 PM10/23/11

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Looking at your pictures, I noticed in picture #16 on the right side by
R351 and C308 there appears to be something burned. Possibly some sort
of wire jumper.

You'll still need a schematic to see what is supposed to be there, but
it might be an area to check out pretty thoroughly.

Good luck in bringing this old machine back to life!

Curtis

p.s. Love the "repairs" made to the keyboard...NOT!!!!

Enrico lazzerini

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Oct 24, 2011, 4:37:10 PM10/24/11

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Thanks for the reply. I uploaded new photos here:
http://www.flickr.com/photos/67772736@N07/sets/72157627837488485/ .
Unfortunately I did not notice on the board (component side) or under the
card (solder side) no sign of burning. I seem to hear at the power on of
the CRT an high-frequency hiss. Having found the power supply of the
Kaypro-II not working and not knowing whether it is the motherboard, I was
first trying to see if the CRT works. As a signal source I am using the
monochrome output of a PC 8088 XT video card because the kaypro-II accepts
distinct signals: video, Hsync and Vsync. It could be not true that the
polarities of these signals are useful as a signal generator to test the
video section of Kaypro-II.
Any suggestions would be great. The schematic much more.

W3VH

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Oct 27, 2011, 3:32:30 AM10/27/11

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On Oct 24, 4:37 pm, Enrico lazzerini <enrico.lazzer...@tiscali.it>
wrote:

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THe high pitched hiss could mean a bad yoke or flyback xformer and
with nothing on the screen i would lean towards flyback ... if you
have the means
you should check the high voltage at the anode but be very careful
and iI mean VERY careful it is High voltage I believe on the order of
12kv.

Enrico lazzerini

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Oct 31, 2011, 1:15:09 PM10/31/11

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Well, while the cathode of the CRT was light, the screen of the crt was
turnoff. I leave the address of some detailed pics below, and i tryed to
see if come out a shoke from the flayback transformer but nothing come out.

Where could i to find its relpace??

Other info:
1) on the PCB
SN 23989586 K10MRDO
Toshiba 23879862 TLC-134-T-V-O
There is a chip NEC 牌C1031H2
Flyback transformer with those info: TFB1026 2L24DS
2) on the back of the CRT
CRT Monitor LR30477 E39164 E2728531 2A13 3D Hu

http:\\elazzerini.interfree.it\Kayvideo\Foto2768.jpg
http:\\elazzerini.interfree.it\Kayvideo\Foto2771.jpg
http:\\elazzerini.interfree.it\Kayvideo\Foto2772.jpg
http:\\elazzerini.interfree.it\Kayvideo\Foto2773.jpg
http:\\elazzerini.interfree.it\Kayvideo\Foto2774.jpg
http:\\elazzerini.interfree.it\Kayvideo\Foto2775.jpg
http:\\elazzerini.interfree.it\Kayvideo\Foto2776.jpg
http:\\elazzerini.interfree.it\Kayvideo\Foto2777.jpg
http:\\elazzerini.interfree.it\Kayvideo\Foto2778.jpg
http:\\elazzerini.interfree.it\Kayvideo\Foto2780.jpg
http:\\elazzerini.interfree.it\Kayvideo\Foto2781.jpg
http:\\elazzerini.interfree.it\Kayvideo\Foto2782.jpg
http:\\elazzerini.interfree.it\Kayvideo\Foto2783.jpg

Thanks in advance for any support.

Enrico

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G. Beat

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Nov 8, 2011, 12:07:18 PM11/8/11

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Enrico -

DOTRONIX supplied (and had replacement CRTs and monitor parts) for the
Kaypro computer.
Contact them for your inquiry.
http://www.dotronix.com/

Dotronix Technology, Inc.
60 1st Street SE
New Brighton, MN 55112
Phone Number: +1 (651) 633-1742
Fax Number: +1 (651) 633-2152

For sales, product information, or other inquires, please eMail: sales
AT dotronix DOT com.
For service and repairs, please eMail: service AT dotronix DOT com.
Contact Kurt Sadler ksadler AT dotronix DOT com

==
"CHILTON'S GUIDE TO KAYPRO REPAIR AND MAINTENANCE" by Gene B.
Williams,
copyright 1985. ISBN: 0-8019-7626-X.
http://www.amazon.com/Chiltons-Guide-Kaypro-Repair-Maintenance/dp/080197626X

http://www.bitsavers.org/pdf/kaypro/

A flyback transformer (FBT), also called a line output transformer
(LOPT), is a special transformer, which is used for conversion of
energy (current and voltage) in electronic circuits.
It was initially designed to generate high current sawtooth signals at
a relatively high frequency.
FAILURE modes with CRT usage is outlined in this Wikipedia article.
http://en.wikipedia.org/wiki/Flyback_transformer

Replacement flyback transformers are readily available from a number
of distributors ....
you just need to use Google (search engine) AND know distributors that
serve the "Old" Radio/TV/Stereo Repairman industry.

Electronix stocks over 1300 types of Flyback transformers
http://www.electronix.com/flyback-transformer-053x0643001-p-19306.html

MCM Electronics - Flyback-Transformers
http://www.mcmelectronics.com/browse/Flyback-Transformers/0000000177

REPAIR FAQ -- This site features Samuel M. Goldwasser's latest and
greatest "Notes on the Troubleshooting and Repair of..."
series of comprehensive repair guides for consumer electronics
equipment and other household devices.
http://repairfaq.org/

===
On Oct 31, 11:15 am, Enrico lazzerini <enrico.lazzer...@tiscali.it>
wrote:

> Well, while the cathode of the CRT was light, the screen of the crt was
> turnoff. I leave the address of some detailed pics below, and i tryed to
> see if come out a shoke from the flayback transformer but nothing come out.
>
> Where could i to find its relpace??
>
> Other info:
> 1) on the PCB
> SN 23989586 K10MRDO
> Toshiba 23879862 TLC-134-T-V-O

> There is a chip NEC µPC1031H2

> Flyback transformer with those info: TFB1026 2L24DS
> 2) on the back of the CRT
> CRT Monitor LR30477 E39164 E2728531 2A13 3D Hu
>
>

> Thanks in advance for any support.
> Enrico
>

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