sci.electronics.repair - 5 new messages in 4 topics - digest

sci.electronics.repair
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Today's topics:

* Marantz PMD222 cassette recorder - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/7f93ff13ee4b752a?hl=en
* Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge
- 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/9cb107f86fe5df92?hl=en
* Any TV experts here? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/ad793e4d0dda11c6?hl=en
* Kaypro-II : display video to repair - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/9041846df71ea782?hl=en

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TOPIC: Marantz PMD222 cassette recorder
http://groups.google.com/group/sci.electronics.repair/t/7f93ff13ee4b752a?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Nov 5 2011 11:37 am
From: "N_Cook"

hifi-tek <t.hoehler@insightbb.com> wrote in message
news:BMGdnW4gJfR16CjTnZ2dnUVZ_o6dnZ2d@insightbb.com...
> I have a PMD222 cassette recorder with a motor no run problem. I have
> cleaned all the switch contacts,no help. Unsoldered the motor leads, put 3
> volts on them, motor runs fine. Does anyone have a schematic for the motor
> control board or the whole recorder? Help! Thanks, Tom
>
>

But is one of the leaf switches bent a bit, especially the tape-in one that
users can easily upset. Then check any transistor that passes current to the
motor

==============================================================================
TOPIC: Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of
Charge
http://groups.google.com/group/sci.electronics.repair/t/9cb107f86fe5df92?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Nov 5 2011 3:23 pm
From: Jeffrey Angus

On 11/5/2011 9:41 AM, Wild_Bill wrote:
> That's the closest to what I was referring to, Adrian, and maybe the
> little pips/nipples could be trimmed off so it would look like 3
> rectangular LEDs arranged like a mini bar graph.

They do have 10 segment ones available from Mouser.
<http://www.mouser.com/Optoelectronics/LED-Displays/_/N-6j73g?P=1z0yqad&Keyword=bar+graph&FS=True>

Jeff

--
"Everything from Crackers to Coffins"

==============================================================================
TOPIC: Any TV experts here?
http://groups.google.com/group/sci.electronics.repair/t/ad793e4d0dda11c6?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Nov 5 2011 5:00 pm
From: "Phil Allison"

"William Sommerwanker"

>
> You've lost SD reception (SD being 625-line PAL), but not HD, right? As
> far
> as I know, SD and HD use separate tuners. (I think.) I could be that the
> SD
> tuner has gone out.

** The RF stages do not change with SD and HD.

.... Phil

==============================================================================
TOPIC: Kaypro-II : display video to repair
http://groups.google.com/group/sci.electronics.repair/t/9041846df71ea782?hl=en
==============================================================================

== 1 of 2 ==
Date: Sat, Nov 5 2011 8:08 pm
From: Franc Zabkar

On Tue, 1 Nov 2011 16:14:19 +0100, Enrico lazzerini
<enrico.lazzerini@tiscali.it> put finger to keyboard and composed:

>Hi at all,
>I bought an old computer with the wishing to make it alive. Itÿs name is
>Kaypro-II and it has 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?
>I seem to hear at the power on of the CRT an high-frequency hiss and i
>tryed to see if come out a shoke from the flayback transformer but nothing
>come out.

>Other useful 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

With respect, your circuit should not be too difficult to troubleshoot
without a circuit diagram.

From your description, it appears that you are hearing the EHT at
startup. You also appear to have a functioning CRT heater.

I would carefully measure the voltages at G1 (brightness), G2 (CRT
bias), and G3 (focus). See if these voltages vary as you adjust the
Focus and Sub-Bright controls.

Also measure the voltages at the diodes and fusible resistors
connected to the flyback transformer secondary outputs. Perhaps one of
these resistors is open. Also check the resistances of any high-ohm
resistors on the CRT neck PCB and elsewhere on the main PCB.

If you have an oscilloscope, then you could confirm that there is EHT
on the CRT by aiming your scope probe at the face of the CRT. You
should see a radiated flyback pulse.

The uPC1031H2 is a vertical amp IC.

According to the following document, the uPC1031H2 is equivalent to
CD1031, KA2130, LA1385, TA7242, or ECG1245:
http://www.datasheetarchive.com/indexdl/Datasheets-SL8/DSASL00155947.pdf

Datasheet for KA2130:
http://f1chf.free.fr/PDF/KA2130.PDF

Datasheet for CD1031CS:
http://www.datasheetarchive.com/dl/Datasheets-10/DSA-187948.pdf

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

== 2 of 2 ==
Date: Sat, Nov 5 2011 8:56 pm
From: Jeff Liebermann

On Tue, 1 Nov 2011 16:14:19 +0100, Enrico lazzerini
<enrico.lazzerini@tiscali.it> wrote:

>Hi at all,
>I bought an old computer with the wishing to make it alive. It´s name is
>Kaypro-II

Schematic of the logic board in the Kaypro-II:
<http://www.z80.eu/downloads/Kaypro_II_schematics.pdf>
The 3rd sheet shows the video outputs going to the display. Put an
oscilloscope on the vert sync, horiz sync, and video lines and see if
there's any output. If no output, then the problem is probably NOT
the display.

More Kaypro schematics and manuals:
<http://www.bitsavers.org/pdf/kaypro/1484-D_KayproTechnicalManual_Dec84.pdf>
No monitor schematic. It does mention the Toshiba display on Pg 7-2.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

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