Toshiba TV29C90 problem; Image fades to black...

MikeC wrote:

"MikeC" <My_address@end.of.post> wrote in message
news:klZgh.11900$KT2.11894@newsfe2-win.ntli.net...

Folks,

I was expecting that the arcing would be through a film of muck - but it
appears to have been across half an inch of open space.

well it was initially, but arcing burnt it away.

You'll need to replace this bit of sheet, if you run it without or with
a hole, muck will get into the waveguide and it'll screw up, only this
time you may have great difficulty trying to clean it out.

Any sheet plastic that can handle microwaves and steam will do. Self
extinguishing is a real plus.


NT

 

Steve wrote:

Sorry if I was unclear. I was originally asking how to actually
measure the circuit capacitance. I have a handheld meter, however, it
runs at a fixed frequency, and when I hook it up to the circuit, it
measures negative capacitance, so I don't think it will work in this
instance.

Thanks again,
Steve

Make a small LC oscillator where osc f depends on C. Dont connect a C,
connect to the circuit where the crystal goes, so youre using teh
circuits capacitance. Note the frequency produced. Now disconnect and
put fixed caps on there to get the same osc frequency. The capacitance
youve hooked on equals the capacitance of the circuit, and thus the
capacitance your xtal needs to be specced for.

Note use a stabilised supply for this osc.


NT

 

[JR]

Arfa Daily wrote:

"JR" <jrgreene1968@suddenlink.net> wrote in message
news:1166313262.291432.119880@80g2000cwy.googlegroups.com...

JR wrote:
Arfa Daily wrote:
jrgreene1968@suddenlink.net> wrote in message
news:1166295094.094869.311800@j72g2000cwa.googlegroups.com...
Hello, i have a problem with a 3801 denon receiver, ..I bought this
receiver from a guy on the internet, said to be in exellent shape,
when
it arrived, i plugged it in and it will not do anything, no display,
no
standby light, no click when you hit power switch nothing. I have
checked all 7 fuses on the receiver with an ohm meter, they are all
ok.
checked voltage where power cord plugs into board, shows 120 volts,
if
you unplug receiver and checked switched outlet on back of receiver,
the outles show open with ohm meter, unplug yellow and white wire on
transformer to board and now switched outlets are no longer reading
open....does this sound like a power transformer, any way to test?


I don't understand your assertion that the switched outlet reads "open"
with
an ohm meter, then doesn't when the white / yellow lead is unplugged.
Are
you sure you don't mean that you read a short, or at least a low
reading,
when the plug is in, and then an open when it is unplugged ? That
situation
works, as the back panel socket, will be connected in parallel with the
power transformer primary, which is itself switched via a relay. The
fact
that you do read this low value ( I believe ) would indicate that the
primary of the main tx is ok. As the seller said that the unit was ok,
I
would suspect that it might have taken a knock in transport, and you
should
be looking for fractured print on the power input board, particularly
where
any pins from the transformers are connected. I have seen this many
times.
Examine all print around the power input and transformers very
carefully
with a magnifying glass if necessary. I'm willing to bet you will find
your
problem quickly, if you know what you are looking for.






well i have looked it over some more...still havent found much...looked
for fractured print, no luck yet. I did get the dmm back out, to check
voltages...not getting volatge anywhere on the board exept where the
power cord it plugging into board, checked for voltage at the 2 main
fuses..nothing, checked for voltage on every wire on power transformer,
nothing there either

Thanks in advance
Arfa


if i unplug the yellow and white wires from transformer, i then have
voltage at main fuses, plug the connector back in, no voltage at fuses,
also there is 2 red and 1 black wires on transformer...checking between
the red and black shows shorted, the guy i bought it from said he heard
a pop when it quit, and he supposedly replaced fuses....


Ah, then it's not quite as straightforward as you originally implied. I got
the impression that the guy who sold it was saying that it was working when
it left him. I am not liking the sound of popping coming from it. I can make
no sense of the voltage readings you appear to be getting. The system is
straightforward enough if it's the model I think it is. As far as I
remember, there is a standby supply which powers the system micro, and
provides a supply for a relay, which is driven by a power on signal from
said micro. The relay switches power to the primary of the main power
transformer. It is quite common for the thermal fuse in the primary of the
main power transformer to fail, but the symptoms of that are that the unit
powers on, in as much as the relay will click, but nothing else happens, no
display, no sound, nothing. You need to determine if the standby supply is
established, and if not, why not. The incoming power lead should be
connected almost directly to the standby tx primary.

Arfa

well he claims that after the pop and everything shutoff, he replaced
the fuses and it started working. Yet when i received it , no nothing,
so i dont know if he is telling the truth or not. I paid him 300 and he
wont refund, so i basically got burned, just trying to get it to work
so i dont have to pour a alot more into...not sure how much it would
cost at a shop, also no one around here works on them so i would have
to ship...
well no clicking when plugging in or pushing power button..the power
button dont feel right to me either..at least not like my onkyo
receiver...ive about give up...i dont have a schematic to follow, and
so im just guessing

 

[Steve]

Aaah, I get it. That makes sense. I'll have to try it once I get
back in the lab, I'll post what I find.

Thanks for the help, I appreciate it.

Steve

On 16 Dec 2006 17:45:15 -0800, meow2222@care2.com wrote:

Steve wrote:

Sorry if I was unclear. I was originally asking how to actually
measure the circuit capacitance. I have a handheld meter, however, it
runs at a fixed frequency, and when I hook it up to the circuit, it
measures negative capacitance, so I don't think it will work in this
instance.

Thanks again,
Steve

Make a small LC oscillator where osc f depends on C. Dont connect a C,
connect to the circuit where the crystal goes, so youre using teh
circuits capacitance. Note the frequency produced. Now disconnect and
put fixed caps on there to get the same osc frequency. The capacitance
youve hooked on equals the capacitance of the circuit, and thus the
capacitance your xtal needs to be specced for.

Note use a stabilised supply for this osc.


NT

 

[Jim Land]

jrgreene1968@suddenlink.net wrote in news:1166295094.094869.311800
@j72g2000cwa.googlegroups.com:

Hello, i have a problem with a 3801 denon receiver, ..I bought this
receiver from a guy on the internet, said to be in exellent shape, when
it arrived, i plugged it in and it will not do anything, no display, no
standby light, no click when you hit power switch nothing.

DOA. Return it.

 

[JR]

Jim Land NO SPAM wrote:

jrgreene1968@suddenlink.net wrote in news:1166295094.094869.311800
@j72g2000cwa.googlegroups.com:

Hello, i have a problem with a 3801 denon receiver, ..I bought this
receiver from a guy on the internet, said to be in exellent shape, when
it arrived, i plugged it in and it will not do anything, no display, no
standby light, no click when you hit power switch nothing.

DOA. Return it.

he refuses to refund money...tried filing a claim with paypal...no
luck...im stuck with it

 

[DeserTBoB]

On 16 Dec 2006 14:52:48 -0800, "elkhound" <elkhound68@yahoo.com>
wrote:

http://cgi.ebay<snip

It's "duty-honor-country" aka aka "elkhound" aka "66fourdoor" aka
Charlie Nudo of Drums, PA again, selling his overpriced crap gleaned
from dead coal miners' estate sales and Goodwill stores..

Please take his original post and forward it, with headers, to:

spam@ebay.com
groups-abuse@google.com
abuse@epix.net

This lunatic is exactly the reason groups like this have to go to mail
lists or web-based forums. Please help get some more of his accounts
tossed. He's lost 15 on Google and 3 on eBay already.

 

[mhancock84]

"just purchased" from a friend of a friend, no warranty.....


--
mhancock84
------------------------------------------------------------------------
mhancock84's Profile: http://www.futurehardware.in/member.php?userid=308
View this thread: http://www.futurehardware.in/showthread.php?t=241635

Future Hardware - http://www.futurehardware.in

 

[Nick]

"t w" <tw100uk@ntlworld.com> wrote in message
news:OS_gh.4385$1W1.1890@newsfe4-win.ntli.net...

Try MARK5

He meant to say: http://www.mark5.co.uk/search.php

Search for 'rectifier'. Pages of 'em; all sorts of voltages .....
Sorry & yes. I've found them very helpful

Thanks both, interesting site. One component seems to fit the bill
(SKV1/2B3000/2700-1.2) though it's listed as POA. I'll give them a call on
Monday. I just hope they're not a silly price or minimum order qty as I can
get a replacement 'scope for 75 quid...

Nick

 

[Mark D. Zacharias]

JR wrote:

Jim Land NO SPAM wrote:
jrgreene1968@suddenlink.net wrote in news:1166295094.094869.311800
@j72g2000cwa.googlegroups.com:

Hello, i have a problem with a 3801 denon receiver, ..I bought this
receiver from a guy on the internet, said to be in exellent shape,
when it arrived, i plugged it in and it will not do anything, no
display, no standby light, no click when you hit power switch
nothing.

DOA. Return it.

he refuses to refund money...tried filing a claim with paypal...no
luck...im stuck with it

I might be able to send a PDF of the manual - it would be a pretty big PDF.
What size attachment can you take, and is

jrgreene1968ATsuddenlink.net

a valid e-mail address?

Mark Z.

 

[JR]

Mark D. Zacharias wrote:

JR wrote:
Jim Land NO SPAM wrote:
jrgreene1968@suddenlink.net wrote in news:1166295094.094869.311800
@j72g2000cwa.googlegroups.com:

Hello, i have a problem with a 3801 denon receiver, ..I bought this
receiver from a guy on the internet, said to be in exellent shape,
when it arrived, i plugged it in and it will not do anything, no
display, no standby light, no click when you hit power switch
nothing.

DOA. Return it.

he refuses to refund money...tried filing a claim with paypal...no
luck...im stuck with it

I might be able to send a PDF of the manual - it would be a pretty big PDF.
What size attachment can you take, and is

jrgreene1968ATsuddenlink.net

a valid e-mail address?

Mark Z.

man that would be great...i should be able to accept a large
attachment, and yes that is the right e-mail addy

Thanks alot

 

[Mike]

In article <1166061269.592965.89730@f1g2000cwa.googlegroups.com>,
<meow2222@care2.com> wrote:

To keep the strike voltage up?

The strike voltage changes if light gets to them?

I wonder if that explains why a neon (integral resistor) fitted in a piece
of equipment here flickers intermittently when it's in the dark, but
lights reliably when illumination falls on it.

This is not a wind-up!

At first it seemed that it only flickered when the fluorescent light in
the room was turned off, which led to thoughts of some bizarre wiring
related error ... but then it turned out that it also responded to
torchlight ... so light was the common factor.

Never seen it before on any other neons, so it might be just a marginal
one!
--
--------------------------------------+------------------------------------
Mike Brown: mjb[at]pootle.demon.co.uk | http://www.pootle.demon.co.uk/
Pluto needs full planet status! http://www.cafepress.com/LeavePlutoIn

 

[Mark D. Zacharias]

I'll see what I can do. If you need me I'm at

mzacharias@labolgcbs.net

and reverse the domain name

mz

JR wrote:

Mark D. Zacharias wrote:
JR wrote:
Jim Land NO SPAM wrote:
jrgreene1968@suddenlink.net wrote in news:1166295094.094869.311800
@j72g2000cwa.googlegroups.com:

Hello, i have a problem with a 3801 denon receiver, ..I bought
this receiver from a guy on the internet, said to be in exellent
shape, when it arrived, i plugged it in and it will not do
anything, no display, no standby light, no click when you hit
power switch nothing.

DOA. Return it.

he refuses to refund money...tried filing a claim with paypal...no
luck...im stuck with it

I might be able to send a PDF of the manual - it would be a pretty
big PDF. What size attachment can you take, and is

jrgreene1968ATsuddenlink.net

a valid e-mail address?

Mark Z.

man that would be great...i should be able to accept a large
attachment, and yes that is the right e-mail addy

Thanks alot

 

[Cheemag]

On Sun, 17 Dec 2006 10:09:25 -0000, "Nick" <nick~newsaccount@btinternet.com>
wrote:

"t w" <tw100uk@ntlworld.com> wrote in message
news:OS_gh.4385$1W1.1890@newsfe4-win.ntli.net...
Try MARK5

He meant to say: http://www.mark5.co.uk/search.php

Search for 'rectifier'. Pages of 'em; all sorts of voltages .....
Sorry & yes. I've found them very helpful

Thanks both, interesting site. One component seems to fit the bill
(SKV1/2B3000/2700-1.2) though it's listed as POA. I'll give them a call on
Monday. I just hope they're not a silly price or minimum order qty as I can
get a replacement 'scope for 75 quid...

If that fails, then you can try the string of diodes suggested further
up the log. Should work.

--

73,
Jim, G4RGA

 

[David Naylor]

Chris F. wrote:

Just thought I'd see if anyone knows of some common problems and fixes,
before spending any great deal of time or money on this. Sometimes the set
starts for a while then quits, other times the switching supply will sputter
for a few seconds and fail (the red diagnostic LED then lights brightly). No
cold solder to be seen, and the caps all check good. I'm leaning towards a
bad switching regulator IC (STR-M6511) and/or optoisolator, but I'm really
not sure how to confirm this without replacing anything. Disconnecting the
loads from the secondary side of the supply (one at a time) does not change
the symptom.
Thanks for any advice.

Even though the caps check good they are I'm sure dried out and failing

change out all the large caps near the regulator , or fet it the primary
of your supply I doubt the fet is bad they either work or don't and
short out

 

[Dave]

"JR" <jrgreene1968@suddenlink.net> wrote in message
news:1166321019.427974.172970@f1g2000cwa.googlegroups.com...

well he claims that after the pop and everything shutoff, he replaced
the fuses and it started working. Yet when i received it , no nothing,
so i dont know if he is telling the truth or not. I paid him 300 and he
wont refund, so i basically got burned, just trying to get it to work
so i dont have to pour a alot more into...

I've found that paypal is absolutely NO help whatsoever in these types of
disputes... their "buyer protection" hooplah is a load of crap. One time I
did not receive a <relatively expensive> item which I purchased on eBay and
paid for with paypal. Now it doesn't get any more straightforward than
that. I paid for something which I did not get. Well, I can't remember the
rationale, but PayPal didn't seem to think it had anything to do with
them...

However, I have also found that VISA has been extremely helpful... if I get
burned on any type of internet purchase, my VISA issuer will cover it when
others will not.

LEAVE NEGATIVE FEEDBACK ON EBAY FOR THIS TURD.

good luck with the amp, you'll get it going. Power problems are about the
easiest to diagnose although not necessarily the cheapest to fix...

 

[John Robertson]

On 2006-12-16 11:38:17 -0800, "Nick" <nick~newsaccount@btinternet.com> said:

My Gould scope has died, it seems that the EHT supply has died. This is a
2.5kV rail supplied from a 950V secondary and a charge pump. The diodes
appear to be blown (I set my variable PSU current limit to 20mA then wound
up the voltage to measure Vf - the PSU goes up to 30V, there can't be THAT
many junctions in a package 10mm long!)

The scope manual lists them as "IJK60TR 6kV"

Some Googling suggests FM50 or SL1200, but I can't find them either. In fact
diodes with this voltage rating seem quite rare. I know I could stack some
lower voltage diodes (and bleed resistors) but space is a bit limited.

Can anyone suggest a replacement, or supplier in the UK?

Thanks
Nick

If all else fails find an old 1970s B&W TV and steal it's HV inline
diode (LOPT HV diode to you folks across the pond). Or an early
computer green screen monitor.

John :-#)#
--
(Please post followups or tech enquires to the newsgroup) John's
Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 Call
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com "Old pinballers never die, they
just flip out."

 

[Homer J Simpson]

"Dave" <dspear99ca@yahoo.delete.com> wrote in message
news:Hryhh.81645$hn.12460@edtnps82...

I've found that paypal is absolutely NO help whatsoever in these types of
disputes... their "buyer protection" hooplah is a load of crap. One time
I did not receive a <relatively expensive> item which I purchased on eBay
and paid for with paypal. Now it doesn't get any more straightforward
than that. I paid for something which I did not get. Well, I can't
remember the rationale, but PayPal didn't seem to think it had anything to
do with them...

It's taken a while but they are actually pretty good now. I've had half a
dozen full refunds from them for fake items or non ships.

You MUST file within the deadlines. Even if you think the guy MIGHT still
ship, FILE! You can always cancel the complaint if he comes through.

http://groups.yahoo.com/group/Bad-eBay-Sellers
--

 

[Homer J Simpson]

<helee4@hotmail.com> wrote in message
news:1166467960.828169.79030@n67g2000cwd.googlegroups.com...

I have a R/C car reciever (Kyosho Mini-z) which has become very poor
range recently. I have checked battery both on the transmitter and at
the car, crystal, and wiring, they all seems to be fine. The symptom
is if I have both the transmitter and the car switched on, the car will
twitch (the servo) badly, and the motor is start to running on its own
without me pressing anything.

What happens if the transmitter is switched off?

 

kevin.pavin@gmail.com wrote:

Hi all,

I have a small surface mount amplifer/filter chip on a packed PCB that
I need to replace. In order to solder in the new one I obviously need
to desolder the old one first being as careful as possible not to
damage anything else on the board. I've never desoldered before and
was wondering if someone could give me the basics or atleast point me
to a tutorial for desoldering in this type of application. Thanks so
much for any advice,

Kev

What type of package?