7 new messages in 6 topics - digest

sci.electronics.repair
http://groups.google.com/group/sci.electronics.repair

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Today's topics:

* Sony verse Mitsubishi - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/fb701dc25589bf9b
* Those cheap 12vdc-120vac inverters - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/3f521f57268fcb60
* Scan lines at top when flyback replaced! RCA F32650 - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/22736a714e928876
* Sony HCD-MG510AV 60 cd receiver w/surround and A/V jacks - WONT TURN ON - 2
messages, 1 author
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/14a64fcfeedabeb4
* for sale ps 3 at $500usd 60gb - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/6f0b93d5aa8016ee
* I fixed my Aiwa CD Player! - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/589dca39119aea70

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TOPIC: Sony verse Mitsubishi
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/fb701dc25589bf9b
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== 1 of 1 ==
Date: Thurs, Dec 7 2006 7:03
pm
From: "Golf"

I am looking at buying a rear projection HDTV. I'm partial to Hitachi,
but am looking at the Sony KDS line, and the Mits DLP's. From a tech
stand point, which would tend to be the long term runner between these
technologies as far as dependability? Any thoughts would be greatful.
Thanks group.

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TOPIC: Those cheap 12vdc-120vac inverters
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/3f521f57268fcb60
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== 1 of 1 ==
Date: Fri, Dec 8 2006 4:22
am
From: "William R. Walsh"

Hi!

> 1. What kind of waveform do they put out? Square wave?

Dunno for sure...I've seen references to modified sine wave units.

> 2. Is it possible to damage a piece of electronics using one? Plugging in
> a radio, tv, laptop PC, what could the inverter do that would damage the
> electronics?

Yes, it could be. I have a StatPower Portawattz (or something similar)
inverter that I bought reconditioned several years ago. The manual that came
with it had several things to say about this topic. I don't recall what all
was mentioned, but cordless drill chargers with notices printed about high
voltage present near the charging contacts were on it.

The only thing I've ever burned up or damaged on it was an X-10 remote
control module. (Don't ask. :-) ) I've run computers, TV sets, box fans,
printers, clocks (with varying results in terms of clock accuracy), a stereo
receiver, laptop power bricks, and even a few lamps. They all worked
acceptably well.

> 3. If the electronics draws too many amps from the inverter, what will be
> the result? Damaged inverter? Damaged electronics?

The inverter I have has been pretty good about this. It simply shuts down
with a loud beep and a red LED if it is overloaded or the battery voltage
falls below 10VDC. Any behavior is possible, but bad things generally
shouldn't happen. The worst case scenario that I'd consider acceptable would
be failure of a fuse in the inverter. Anything else failing inside it would
seem to indicate poor design.

William

==============================================================================
TOPIC: Scan lines at top when flyback replaced! RCA F32650
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/22736a714e928876
==============================================================================

== 1 of 1 ==
Date: Thurs, Dec 7 2006 9:14
pm
From: jtcoosie@ameritech.net

first off please excuse the spelling i'm an electronic tech not an
english major.

i have the exact same problem

after adjusting vert settings in the sevice menu (this fixed the scan
lines) except when the screen is black during a channel change or vid
input change which leads me to.......

i noticed another problem

when watching cnn or espn when the picture gets brighter the running
ticker on the bottom of the screen will boom out (enlarge, picture size
increeses) when the image gets darker the picture shrinks ????????????

i adjusted the screen voltage to 211 volts as shown on the sams
photofact (set 4792.pdf) that the suplier of the flyback was kind
enough to send me. this gave me to dark of a screen
and the osd menu black. turnning up the screen control till osd is good
(requires very little adjustment very touchie ) now when monitoring the
screen voltage at pin 7 of the crt the voltage varries from 206-224v
depending what is on the screen dark pic or bright pic. if camera
flashes are displayed the voltage really goes up and down.

also to let you know i replaced the H.O.T. (TL02),
tp20,tp23,tp22,dp22,dp31,rp21 (all fried by the flyback),

and all the caps except the smd's in the LV-PS with parts scavanaged
from a good CTC203 chassis witch is almost identical to the ATC113. in
the lv and hv sections. in an attemp to correct this problem.

130v source in th LV-PS stays rock solid at 129.8v.
17v source is at 16v
9v source is at 8.8v
5.2v source is at 5.2v
-11.7 source is at -11.7v
15.3v source is at 15.2v
and my 14v sorce (tp21) on print is at 16v. this is part of the
flyback supply it feeds the sence curciut TP553 and the tilt curcuit
and coil.

i think its the flyback or the crt?

I'm Frustrated!!!!

COOSIE

Dani wrote:
> Slight tweaking in the EEPROM has ALWAYS fixed these units after a
> generic flyback.
> Also, adjust the G-2 so it's not too high. Dani.
>
>
> tyrone_park@hotmail.com wrote:
> > When I replaced the flyback transformer & HOT in this set (original
> > faulty parts), I have a few scan lines visible at the top of the
> > screen. I cannot seem to get any adjustment to fix it. The flyback is
> > a substitute replacement from the original and I feel it may have
> > caused this problem. The picture is fine except for these scan lines
> > that are visible. Has anyone fixed or seen this problem after
> > replacing the original flyback with a sub? What can be done to correct
> > this? Supplier says original is NLA.

==============================================================================
TOPIC: Sony HCD-MG510AV 60 cd receiver w/surround and A/V jacks - WONT TURN ON
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/14a64fcfeedabeb4
==============================================================================

== 1 of 2 ==
Date: Thurs, Dec 7 2006 9:17
pm
From: "paragon66x"

> If it seems to turn on normally, with the speaker relay coming on after the
> usual delay, and just no display, there is a chance that only the -30 volt
> line for the display is down (or some other section of the power supply).
> There is a 100 ohm fusible resistor on the power board, R901, near the large
> connector which goes to the main board. This resistor could be bad.
>
> There is also a separate fuse board, and there could be bad fuses there -
> don't recall if you said you had checked those.
>
>
> Mark Z.

I actually checked the "hidden" fuses on the power supply board above
the transformer a while back. I went ahead and removed the power
supply from the stereo again tonight, removed the fuses again and they
checked ok for continuity. I then checked the resistors on the board
and they seemed to check within tolerance - one of these was the R901
you speak of. I went ahead and checked the switching diodes (they
seemed ok) and the two 1N002 diodes. One of the 1N002's (D902) tested
kind of odd so I pulled one leg out and it checks out the way it
should. When I put it back in the board it cheked out the same as
before across the ends - ".051" and it didn't matter which way I had
the black and red leads of my DMM. As you probably already know these
should ideally check between .4 - .6 one way and "OL" the other. So I
am not sure why this diode is reading this way, but I did notice one of
the traces is going to a small transistor Q901, but I do not recognize
this as one I know how to check/ meter out The numbers on it are C107
(top line) and M131 (bottom line). On the same trace going the other
way it leads to an OMRON 5VDC black box (not sure if its function).
Does this diode reading sound suspicious or like soemthing else on the
board is causing this goofy reading? Considering I pulled one leg out
and it read ok I beleive the diode to be good. Other than this, I
don't readily see anything that looks out of the ordinary. Any other
ideas for me to try? I will leave the power supply on my bench
overnight. Thanks for your help this far. John

== 2 of 2 ==
Date: Thurs, Dec 7 2006 9:22
pm
From: "paragon66x"

Oh and as far as it turning on normally, I am not sure if I am
misleading you or not. The thing doesn't turn on. When you press the
power button it doesn't do jack. When you plug it in though it does
put power to the power button LED and it looks like there is fire going
to the cassette motor too as it lunges forward a bit. But that's all
she does other than make the click after plugging it in, but I don't
know what that click means - just seems like it always did that. John

==============================================================================
TOPIC: for sale ps 3 at $500usd 60gb
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/6f0b93d5aa8016ee
==============================================================================

== 1 of 1 ==
Date: Thurs, Dec 7 2006 11:08
pm
From: connectmobiles500@yahoo.com

All,this are brand ne game comes with, Wireless Controller, AC Power
Cord, AV Cable, Ethernet Cable, USB Cable, along with manual for the
system. Accessories: System x 1 Wireless controller x 1 AC power cord x
1 AV cable x 1 (NTSC (US & Canada)) Ethernet cable x 1 USB cable x 1
Printed materials x 1 set also comes with 1year international
warranty.

contact.connectmobiles500@yahoo.com

==============================================================================
TOPIC: I fixed my Aiwa CD Player!
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/589dca39119aea70
==============================================================================

== 1 of 1 ==
Date: Thurs, Dec 7 2006 11:21
pm
From: "aasdf"

Thanks for the replies guys. Didn't realize this would generate so
much controversy. I'm just a shmo who had a piece of equipment he
thought wasn't ever going to work again, and certainly wasn't willing
to pay half the purchase price to get it fixed. I definitely am not an
engineer nor would I recommend any electronic repairman do what I did.
But I didn't have any fancy gadgets that you mention to analyze the
system, I just had a philips head screwdriver. I don't even know what
that pot does! I assume it turns up the power of the laser. But I was
just thrilled it worked at all that I figured I'd put it here for
anybody who is my situation. It was a little project to distract
myself from studying for finals :)

Keep up the good work and thanks for the informative replies!

aasdf

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