Toshiba TV29C90 problem; Image fades to black...

[Phil Allison]

micky wrote:

I thought all ceramic fuses were slo-blo, but this one is embossed
F12H250 and some webpages say that F means fast-blow????

** Ceramic fuses come in all types, fast, medium and slo- blow as well as HRC.

HRC = High Rupture Current and are found in some uW ovens.

Nothing I read decribes why a microwave should need ceramic or slow-blo
(in the power part, not the high voltage part).

** Ceramic fuses are specified as they do not shatter when heavily overloaded.
Slow blow is needed to cope with inrush surges from the transformer, if there is one.

" If a high voltage comes down the electrical line, the fuse element
will melt.

** Absurd.

From before
According to the label on the back "The input is 1400 watts, but it's a
220 volt device, so that's less than 7amps normally. So, 10, right?
Unless F12 in F12H250 at the top means 12 amps? " And the home.repair
people told me it did, but the web says F means fast-blow.

** Single plated wire "F? fuses are in fact rather slow and tolerate brief surges of say 5 times their rating.



..... Phil

 

[Phil Allison]

Phil Allison wrote:

*Correction:


** Single strand, plated wire "F" fuses of 10 amp raring or more are in fact rather slow and tolerate brief surges of say 5 times their rating.



..... Phil

 

On Friday, 29 March 2019 13:14:14 UTC, micky wrote:

To recap for the scientists: What size fuse to use in a 22V microwave:

In alt.home.repair, on Thu, 28 Mar 2019 19:07:29 -0500, Dean Hoffman
dh0496@windstream.net> wrote:

On 3/28/19 7:00 PM, hubops@ccanoemail.ca wrote:


12a

Okay. I'll look for 12 amps, I'm glad I asked.
But I may have to settle for 10.


Yep - the problem that caused the 12 amp to blow
has surely cleared itself up by now - so a 10 amp is perfect !
.. or not. >> John T.

I suspect that was tongue in cheek. If not, fuses fail just
like everything else involving humans. I've changed a lot of them over the years
without having to do anything else.

LOL. I wasn't living here when it broke; I don't know what they did to
it.

By the same token, I'm leaving and I wanted to either put in the right
fuse or leave a note inside the case for the new owner (my roommate
already bought a replacement and they plan to put this one in the lobby
for someone to take.)

The second store I called had it, even 12 amps, not just 10, but as I
expected, only fast-blow. The original was ceramic.

I thought all ceramic fuses were slo-blo, but this one is embossed
F12H250 and some webpages say that F means fast-blow????
"The types of fuses include long-time-lag or super-time-lag (TT),
fast-acting fuses (FF), quick-blow fuses (F) and slow-blow or time-lag
fuses (T)"
https://www.hunker.com/13418825/difference-between-ceramic-glass-fuses

Nothing I read decribes why a microwave should need ceramic or slow-blo
(in the power part, not the high voltage part).

One page says " Glass has a low rupturing point, such as 15 amperes."

That's fine since it's a 12 amp fuse, and the normal usage is about 7
amps.

" If a high voltage comes down the electrical line, the fuse element
will melt.

Are there really surges that come down the line that increase the
amperage for normally 7 to over 12?

"The tiny glass fuses are great for small items that don't draw a heavy
amount of current and blow on a regular basis. They don't perform well
outdoors and can shatter when placed in high temperatures due to its low
thermal stability."

Microwave is not used outdoors or at high temperatures.


From before
According to the label on the back "The input is 1400 watts, but it's a
220 volt device, so that's less than 7amps normally. So, 10, right?
Unless F12 in F12H250 at the top means 12 amps? " And the home.repair
people told me it did, but the web says F means fast-blow.

It's a Crystal, model wp900AP23, but no schematic could I find on the
web and the one taped inside just shows fuse, no details.

If it's F12H250 then you need to fit a 12A F12H250 of the same size & construction type. Fuses are more of a big deal in nukes than other appliances. Don't cut corners on them.


NT

 

[Lucifer]

On Fri, 29 Mar 2019 16:14:10 +0300, micky <NONONOmisc07@bigfoot.com>
wrote:

>To recap for the scientists: What size fuse to use in a 22V microwave:

The size would be 6 mm if there was such a thing as a 22 volt
microwave.

 

[Lucifer]

On Fri, 29 Mar 2019 14:37:03 +0100, Look165 <look165@numericable.fr>
wrote:

I've seen no fuse in mine.

Consider the protection is outside and 16A is enough.

https://en.wikipedia.org/wiki/Usenet_quoting

micky a écrit le 29/03/2019 ŕ 14:14 :

To recap for the scientists: What size fuse to use in a 22V microwave:

In alt.home.repair, on Thu, 28 Mar 2019 19:07:29 -0500, Dean Hoffman
dh0496@windstream.net> wrote:

On 3/28/19 7:00 PM, hubops@ccanoemail.ca wrote:
12a
Okay. I'll look for 12 amps, I'm glad I asked.
But I may have to settle for 10.

Yep - the problem that caused the 12 amp to blow
has surely cleared itself up by now - so a 10 amp is perfect !
.. or not. >> John T.

I suspect that was tongue in cheek. If not, fuses fail just
like everything else involving humans. I've changed a lot of them over the years
without having to do anything else.
LOL. I wasn't living here when it broke; I don't know what they did to
it.

By the same token, I'm leaving and I wanted to either put in the right
fuse or leave a note inside the case for the new owner (my roommate
already bought a replacement and they plan to put this one in the lobby
for someone to take.)

The second store I called had it, even 12 amps, not just 10, but as I
expected, only fast-blow. The original was ceramic.

I thought all ceramic fuses were slo-blo, but this one is embossed
F12H250 and some webpages say that F means fast-blow????
"The types of fuses include long-time-lag or super-time-lag (TT),
fast-acting fuses (FF), quick-blow fuses (F) and slow-blow or time-lag
fuses (T)"
https://www.hunker.com/13418825/difference-between-ceramic-glass-fuses

Nothing I read decribes why a microwave should need ceramic or slow-blo
(in the power part, not the high voltage part).

One page says " Glass has a low rupturing point, such as 15 amperes."

That's fine since it's a 12 amp fuse, and the normal usage is about 7
amps.

" If a high voltage comes down the electrical line, the fuse element
will melt.

Are there really surges that come down the line that increase the
amperage for normally 7 to over 12?

"The tiny glass fuses are great for small items that don't draw a heavy
amount of current and blow on a regular basis. They don't perform well
outdoors and can shatter when placed in high temperatures due to its low
thermal stability."

Microwave is not used outdoors or at high temperatures.


From before
According to the label on the back "The input is 1400 watts, but it's a
220 volt device, so that's less than 7amps normally. So, 10, right?
Unless F12 in F12H250 at the top means 12 amps? " And the home.repair
people told me it did, but the web says F means fast-blow.

It's a Crystal, model wp900AP23, but no schematic could I find on the
web and the one taped inside just shows fuse, no details.

 

[Lucifer]

On Fri, 29 Mar 2019 14:30:10 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:

micky wrote:



I thought all ceramic fuses were slo-blo, but this one is embossed
F12H250 and some webpages say that F means fast-blow????


** Ceramic fuses come in all types, fast, medium and slo- blow as well as HRC.

HRC = High Rupture Current and are found in some uW ovens.

I had a 5 volt UPS from a Data General mini computer which had
a 200 amp HRC fuse.

Nothing I read decribes why a microwave should need ceramic or slow-blo
(in the power part, not the high voltage part).



** Ceramic fuses are specified as they do not shatter when heavily overloaded.
Slow blow is needed to cope with inrush surges from the transformer, if there is one.


" If a high voltage comes down the electrical line, the fuse element
will melt.


** Absurd.


From before
According to the label on the back "The input is 1400 watts, but it's a
220 volt device, so that's less than 7amps normally. So, 10, right?
Unless F12 in F12H250 at the top means 12 amps? " And the home.repair
people told me it did, but the web says F means fast-blow.


** Single plated wire "F? fuses are in fact rather slow and tolerate brief surges of say 5 times their rating.



.... Phil

 

[Martin Gregorie]

On Sat, 30 Mar 2019 21:04:14 +1100, Lucifer wrote:

I had a 5 volt UPS from a Data General mini computer which had a 200 amp
HRC fuse.

Unsurprising: old computers ate power.

The CPU of 1902S mainframe I was sysadmin for in 1972 was entirely solid
state (discrete transistors) and with 32 kWords (96kB equivalent) of
ferrite core memory. That CPU used 20KW. Add in 6 tape decks, two disk
drives, printer, cardreader and a comms multiplexor and the system
consumed 40 KW when fully up and running - typical for kit in that era.


--
Martin | martin at
Gregorie | gregorie dot org

 

[Stephen Wolstenholme]

On Sat, 30 Mar 2019 12:02:20 +0000 (UTC), Martin Gregorie
<martin@mydomain.invalid> wrote:

On Sat, 30 Mar 2019 21:04:14 +1100, Lucifer wrote:

I had a 5 volt UPS from a Data General mini computer which had a 200 amp
HRC fuse.

Unsurprising: old computers ate power.

The CPU of 1902S mainframe I was sysadmin for in 1972 was entirely solid
state (discrete transistors) and with 32 kWords (96kB equivalent) of
ferrite core memory. That CPU used 20KW. Add in 6 tape decks, two disk
drives, printer, cardreader and a comms multiplexor and the system
consumed 40 KW when fully up and running - typical for kit in that era.

I never worked on 1902S but I worked on System 4 and the largest
2900's. The current demands were very high but generally low voltage
so some engineers would work on live power supplies. Mending the 3
phase mains primary supply in the middle of the night could be
dangerous. The secondary output was much lower voltage but high
current. We kept an adjustable spanner that had been dropped onto the
5.6V DC supply. It was to remind some engineers of the power involved.
The spanner had blown like a fuse. I can't remember the current limit
but it was huge!

Steve

--
http://www.npsnn.com

 

[Martin Gregorie]

On Sat, 30 Mar 2019 13:28:35 +0000, Stephen Wolstenholme wrote:

On Sat, 30 Mar 2019 12:02:20 +0000 (UTC), Martin Gregorie
martin@mydomain.invalid> wrote:

On Sat, 30 Mar 2019 21:04:14 +1100, Lucifer wrote:

I had a 5 volt UPS from a Data General mini computer which had a 200
amp HRC fuse.

Unsurprising: old computers ate power.

The CPU of 1902S mainframe I was sysadmin for in 1972 was entirely solid
state (discrete transistors) and with 32 kWords (96kB equivalent) of
ferrite core memory. That CPU used 20KW. Add in 6 tape decks, two disk
drives, printer, cardreader and a comms multiplexor and the system
consumed 40 KW when fully up and running - typical for kit in that era.

I never worked on 1902S but I worked on System 4 and the largest 2900's.
The current demands were very high but generally low voltage so some
engineers would work on live power supplies. Mending the 3 phase mains
primary supply in the middle of the night could be dangerous. The
secondary output was much lower voltage but high current. We kept an
adjustable spanner that had been dropped onto the 5.6V DC supply. It was
to remind some engineers of the power involved.
The spanner had blown like a fuse. I can't remember the current limit
but it was huge!

No System 4 for me - only 1900, 2903 (the 2900 DFC in a different orange
box running microcode to emulate a 1900), and a fair bit of time at the
BBC writing systems for their 2900s.

Somebody working in the computer room managed to drop a short crowbar
into the BBC UPS when it had its covers off, but caught it before it did
any damage - and then had to stand there holding it while the pair of
2960s were shut down and the UPS turned off. Were you there, by any
chance?


--
Martin | martin at
Gregorie | gregorie dot org

 

[Stephen Wolstenholme]

On Sat, 30 Mar 2019 14:57:53 +0000 (UTC), Martin Gregorie
<martin@mydomain.invalid> wrote:

On Sat, 30 Mar 2019 13:28:35 +0000, Stephen Wolstenholme wrote:

On Sat, 30 Mar 2019 12:02:20 +0000 (UTC), Martin Gregorie
martin@mydomain.invalid> wrote:

On Sat, 30 Mar 2019 21:04:14 +1100, Lucifer wrote:

I had a 5 volt UPS from a Data General mini computer which had a 200
amp HRC fuse.

Unsurprising: old computers ate power.

The CPU of 1902S mainframe I was sysadmin for in 1972 was entirely solid
state (discrete transistors) and with 32 kWords (96kB equivalent) of
ferrite core memory. That CPU used 20KW. Add in 6 tape decks, two disk
drives, printer, cardreader and a comms multiplexor and the system
consumed 40 KW when fully up and running - typical for kit in that era.

I never worked on 1902S but I worked on System 4 and the largest 2900's.
The current demands were very high but generally low voltage so some
engineers would work on live power supplies. Mending the 3 phase mains
primary supply in the middle of the night could be dangerous. The
secondary output was much lower voltage but high current. We kept an
adjustable spanner that had been dropped onto the 5.6V DC supply. It was
to remind some engineers of the power involved.
The spanner had blown like a fuse. I can't remember the current limit
but it was huge!

No System 4 for me - only 1900, 2903 (the 2900 DFC in a different orange
box running microcode to emulate a 1900), and a fair bit of time at the
BBC writing systems for their 2900s.

Somebody working in the computer room managed to drop a short crowbar
into the BBC UPS when it had its covers off, but caught it before it did
any damage - and then had to stand there holding it while the pair of
2960s were shut down and the UPS turned off. Were you there, by any
chance?

I never worked on a BBC site. Most of my work was around Manchester. I
started on a LEO3 at the town hall. Then System 4 on shifts at Norweb,
NW Gas, TSB and a few other places during the night. Night calls were
often a long way from Manchester. I once got a call at about 01:00 to
drive to Bristol. When I got to Bristol the site was closed so I drove
back to Manchester. That's about 350 miles for expenses plus 7 hours
overtime at double time. That was quite a lot of money but I would
have preferred to stay in bed.

Steve

--
http://www.npsnn.com

 

Hi I have a sony betamax, I can see even though there is no tape inside, the mechanizem inside is in position like there is a tape inside. Only know this because I have a working beta sony to compare. Any help? When i press power ect it does try to eject but that metal tab piece doesnt move the one that normally grab the tape and brings it around.

 

[whit3rd]

On Tuesday, April 2, 2019 at 8:17:34 PM UTC-7, thetruew...@gmail.com wrote:
> Hi I have a sony betamax, I can see even though there is no tape inside, the mechanizem inside is in position like there is a tape inside. Only know this because I have a working beta sony to compare. Any help? When i press power ect it does try to eject but that metal tab piece doesnt move the one that normally grab the tape and brings it around.

The most likely problem in the current century is a snapped belt (rubber band)
That means you want to open the gizmo, find the rubber scrap that used to
be a belt, measure it, and cut something out of a tire innertube that more-or-less
matches (or get an O-ring the right size from a mechanical-supplies outfit)..

A cleanup and light greasing (silicone grease is messy, but effective) might also help,
and if you find dead insects in the mechanism, those ought to be removed.

Except for the little brittle parts of the heads, a wipe with cotton swabs moistened
with isopropyl alcohol is usually beneficial to the moving and contact-with-tape parts.

 

On Wednesday, 3 April 2019 05:48:34 UTC+1, whit3rd wrote:

On Tuesday, April 2, 2019 at 8:17:34 PM UTC-7, thetruew...@gmail.com wrote:

Hi I have a sony betamax, I can see even though there is no tape inside, the mechanizem inside is in position like there is a tape inside. Only know this because I have a working beta sony to compare. Any help? When i press power ect it does try to eject but that metal tab piece doesnt move the one that normally grab the tape and brings it around.

The most likely problem in the current century is a snapped belt (rubber band)
That means you want to open the gizmo, find the rubber scrap that used to
be a belt, measure it, and cut something out of a tire innertube that more-or-less
matches (or get an O-ring the right size from a mechanical-supplies outfit).

A cleanup and light greasing (silicone grease is messy, but effective) might also help,
and if you find dead insects in the mechanism, those ought to be removed.

Except for the little brittle parts of the heads, a wipe with cotton swabs moistened
with isopropyl alcohol is usually beneficial to the moving and contact-with-tape parts.

I always marvelled at how they simplfied the mechanisms as the years rolled by. Last generation VCRs really didn't have much mechanicals in them.

Beta was 1970s, so probably a handful of belts that have rotted, broken or stretched. Try to resist paying premium belt prices except for places where speed stability is critical.


NT

 

[N_Cook]

On 03/04/2019 06:07, tabbypurr@gmail.com wrote:

On Wednesday, 3 April 2019 05:48:34 UTC+1, whit3rd wrote:
On Tuesday, April 2, 2019 at 8:17:34 PM UTC-7, thetruew...@gmail.com wrote:

Hi I have a sony betamax, I can see even though there is no tape inside, the mechanizem inside is in position like there is a tape inside. Only know this because I have a working beta sony to compare. Any help? When i press power ect it does try to eject but that metal tab piece doesnt move the one that normally grab the tape and brings it around.

The most likely problem in the current century is a snapped belt (rubber band)
That means you want to open the gizmo, find the rubber scrap that used to
be a belt, measure it, and cut something out of a tire innertube that more-or-less
matches (or get an O-ring the right size from a mechanical-supplies outfit).

A cleanup and light greasing (silicone grease is messy, but effective) might also help,
and if you find dead insects in the mechanism, those ought to be removed.

Except for the little brittle parts of the heads, a wipe with cotton swabs moistened
with isopropyl alcohol is usually beneficial to the moving and contact-with-tape parts.

I always marvelled at how they simplfied the mechanisms as the years rolled by. Last generation VCRs really didn't have much mechanicals in them.

Beta was 1970s, so probably a handful of belts that have rotted, broken or stretched. Try to resist paying premium belt prices except for places where speed stability is critical.


NT

All belts need at least checking, including any mode switch belt.
Another age related common defect is cracked plastic of first pinion on
the mode switch motor (plastic on steel does not like temp
changes/brittling of plastic over time)

 

[John-Del]

On Wednesday, April 3, 2019 at 1:07:36 AM UTC-4, tabb...@gmail.com wrote:

Beta was 1970s, so probably a handful of belts that have rotted, broken or stretched.

Well, Sony made Betas up to the early 2000s, so you only missed that by a couple of decades.

 

[amdx]

On 4/3/2019 6:52 AM, John-Del wrote:

On Wednesday, April 3, 2019 at 1:07:36 AM UTC-4, tabb...@gmail.com wrote:


Beta was 1970s, so probably a handful of belts that have rotted, broken or stretched.


Well, Sony made Betas up to the early 2000s, so you only missed that by a couple of decades.

I'm surprised to hear that, I got out of VCR repair in 1994, when I
decided the purchase price for a new VCR was getting so low, that people
would rather buy a new one than pay my repair prices.
I timed it right, I alerted another tech I was leaving so he could take
over my work, I went back 13 months later and he said he only came in 3
days a week to do any repairs that came in.
I did 11,000 repairs in a 10 year stint, but did very little Sony
repair, maybe 1% or 2%. Although in another job (1972) I repaired Sony
1/2" reel to reel video recorders, the AV3600 and AV3650, then later
3/4" Umatic cassette recorder and players, VO-1000 and V0-1600.
In the 80's we had 3 big box electronics franchise stores in our area,
they all boomed when vcr's came out and the sales were very brisk.
We did manufacturer warranty and store warranty repair for all three.
Old memories!
Mikek

 

On Wednesday, 3 April 2019 12:53:00 UTC+1, John-Del wrote:

On Wednesday, April 3, 2019 at 1:07:36 AM UTC-4, tabby wrote:


Beta was 1970s, so probably a handful of belts that have rotted, broken or stretched.


Well, Sony made Betas up to the early 2000s, so you only missed that by a couple of decades.

Betamax was released in 75. It was a home product rather than the earlier Umatic. They may have lingered on in small amounts but they were pretty much dead in the 80s. They lost, IIRC due to failure to license the tech to others. IME most beta decks are late 70s, some early 80s.


NT

 

First of all, model. The original thread was about a Superbeta, all of which used the newer J loader rather than the U loader. Is that what you have ?

If what you say is correct, (not "true" because you have no reason to lie) that means a tape was forced out of there. the J loaders were quite fragile with the arms that wound the tape. They can get out of kilter and just need some friendly persuasion to get back in whack. Gears breaking was rare, and the really wild gears were metal, sheet metal but metal. However the would pop out their tracks and jam up. If a tape was jammed up and wouldn't let the tape out it might very well fail that way.

The way to tell a U loader from a J loader is that the J has two arms grabbing the tape when inserted, the U loader only has one. In a U loader it just goes around a circle like to get the tape around the head. It is important to know which you have. If you give up the model I might know which it is..

The gears are probably OK but they are out of whack. If you can get it here I can probably fix it and I DO have some parts in stock. However that might not be quite practical. I am in the US, Ohio, Cleveland. I worked on tons of these things.

Next best thing is if you got image hosting post some pictures. If I see exactly what state the mech is in I might be able to tell you what to do.

Model and pics. Best I can do. Without that you are fucked. (or bring it or ship it)

Note that if it is not NTSC I cannot confirm correct color. I can confirm good video, the [presence of color, the AFM (sound) carriers and almost everything but I do not have a multirate monitor right now. I can fix the mech, but if it is not NTSC that's pretty much it.

 

[Lucifer]

On Tue, 2 Apr 2019 20:17:31 -0700 (PDT), thetruewillheart@gmail.com
wrote:

Hi I have a sony betamax, I can see even though there is no tape
inside, the mechanizem inside is in position like there is a tape
inside. Only know this because I have a working beta sony to
compare. Any help? When I press power ect it does try to eject but
that metal tab piece doesnt move the one that normally grab the tape
and brings it around.

Sounds like you need to pull it apart.

I have a camcorder that uses a standard beta cassette.

 

On Wednesday, March 11, 2015 at 1:00:49 AM UTC+2, deamf...@yahoo.com wrote:

On Sunday, August 1, 1999 at 9:00:00 AM UTC+2, Raditecnica de Miguel Ricardo wrote:
 


--
raditecnica@mail.telepac.pt


Raditecnica de Miguel Ricardo <raditecnica@mail.telepac.pt
escreveu na mensagem news:...

Hi Peter

 

Maybe I can help you

 

Miguel

 

 

Portugal


--
raditecnica@mail.telepac.pt


Peter Nelson <pnelson1@globalnet.co.uk
escreveu na mensagem news:7ns0t2$b3h$2@gxsn.com...

Anyone got a schematic for this analogue multimeter?

 

Peter


--
Peter Nelson
pnelson1@globalnet.co.uk

Hi all,

Has anybody got the user manual or schematic drawing of this multimeter? I also need it.

Please help!

Thanks!

Deam

Just come across your posting/s. Not sure if you have found a copy of schematic / manual. I do own a 360-TR and provided similar info to someone here in South Africa in 2016. Found my email with info so I can email copy to you if you wish. You can use my email address des.bryington@gmail.com Subject 360-TR. Best wishes