SC1224 Video Cable?

Troubles with your machine? Just want to speak about the latest improvements? This is the place!

Moderators: Mug UK, Zorro 2, Greenious, spiny, Moderator Team

User avatar
Elrond
Retro freak
Retro freak
Posts: 16
Joined: Mon Aug 11, 2003 1:43 am
Location: California

SC1224 Video Cable?

Postby Elrond » Sat Feb 28, 2004 10:40 am

I was playing games on my Atari 520ST when my SC1435 monitor died for no reason. It still turns on, but the picture was dead and would only give off a high pitched sound. I know nothing about fixing things like that, so I proceeded to my garage where I found an SC1224 which was also broken!

I picked up another SC1224 on Ebay that does work.
However, there's one problem. It didn't come with the video signal cable I need to hook the monitor up to the computer. My broken SC1224 has a built in cable, and the SC1435's cable is different. I guess this means I need to somehow find a cable that can be used with my SC1224.
Anybody know where I might buy the one I need?
I hope it doesn't cost much, the monitor itself was only $11.

Also, I was wondering since the SC1224 has vents on both sides but only uses one for one speaker, is it possible to take the Stereo speakers from a SC1435 and upgrade the SC1224 with them? Then again, I'm probably the wrong person to be messing with the electronics. ^^;
Image

simbo

Postby simbo » Sat Feb 28, 2004 11:47 pm

i think what you need is to take your sc1435 monitor to the local tv shop

and ask the guy to repair it at his leasure
also tell him you have a couple more


the sc1435 to atari lead is relativly easy youll find details if you look for the schematic using google

just type in atari schematics
and youll find atari schematic central the site has the details

to get the special plug for atari
in th euk maplin still sell this connector
as for the other end ??15 pin dtype ??

use shielded cable

or better is if the guy cant fix yours
he will wire a cable easy...

keeps him eating also

User avatar
Nutking
Atari maniac
Atari maniac
Posts: 89
Joined: Tue Mar 16, 2004 7:58 pm
Location: Groot Nuttestein
Contact:

Re: SC1224 Video Cable?

Postby Nutking » Fri Mar 19, 2004 9:01 am

Hi,

This sounds funny to me. the sc1224 is the standard ST monitor for high and mid rez as opposed to the sm 124 for hires mono. I should say plug it directly in. There's a 13 pin (well, er... 13 hole actually) output on the back of the ST. I must say I never heard of the 1435 monitor anyway.

good luck, dNK

Elrond wrote:I was playing games on my Atari 520ST when my SC1435 monitor died for no reason. It still turns on, but the picture was dead and would only give off a high pitched sound. I know nothing about fixing things like that, so I proceeded to my garage where I found an SC1224 which was also broken!

I picked up another SC1224 on Ebay that does work.
However, there's one problem. It didn't come with the video signal cable I need to hook the monitor up to the computer. My broken SC1224 has a built in cable, and the SC1435's cable is different. I guess this means I need to somehow find a cable that can be used with my SC1224.
Anybody know where I might buy the one I need?
I hope it doesn't cost much, the monitor itself was only $11.

Also, I was wondering since the SC1224 has vents on both sides but only uses one for one speaker, is it possible to take the Stereo speakers from a SC1435 and upgrade the SC1224 with them? Then again, I'm probably the wrong person to be messing with the electronics. ^^;

User avatar
Nutking
Atari maniac
Atari maniac
Posts: 89
Joined: Tue Mar 16, 2004 7:58 pm
Location: Groot Nuttestein
Contact:

Re: SC1224 Video Cable?

Postby Nutking » Fri Mar 19, 2004 9:05 am

[quote="Nutking"]Hi,

This sounds funny to me. the sc1224 is the standard ST monitor for high and mid rez as opposed to the sm 124 for hires mono. I should say plug it directly in. There's a 13 pin (well, er... 13 hole actually) output on the back of the ST. I must say I never heard of the 1435 monitor anyway.

good luck, dNK
Sorry, 1224 is for low and med rez, not High.
:oops:

User avatar
Ragstaff
Atari Super Hero
Atari Super Hero
Posts: 610
Joined: Mon Oct 20, 2003 3:39 am
Location: Melbourne Australia
Contact:

Postby Ragstaff » Sat May 29, 2004 3:10 am

When the SC1435 gets the "high pitch buzz, no picture", it's generally the output transformer.
I've got about 3 like this now.

I took mine into a TV shop once, and the bloke looked at it for me for free. He said it would cost more for him to fix it than it was worth, but he showed me the component I needed to replace, and said if I could track a replacement down I could do it myself.

Apparently it's not all the traumatic to do, if you can just find yourself another transformer with the right specs.

Of course, whenever talking about opening up TVs/monitors, we must throw in the mandatory warning about high voltages!! It's a dangerous place to be stuffing around if you don't know what you're doing!

simbo

Postby simbo » Sat May 29, 2004 9:13 pm

http://www.tesa.co.nz/lopt/pc.htm

here is a guy in newzeland

http://www.donberg.ie/

another supplier of lopt transformers

http://www.donberg-electronics.com/search.html
this is a good one to try has a search feature

dont give up
on any lopt is a label it has a number say like abc77819-001ap
say this was it
then usualy the manufacurer has a legal obligation to keep spares avalible for the expected duration and life time of there product

with computers this is not fully known
so legaly they MUST stock them all

so just phone around someone will have one in there cupboard

there is literaly millions of types
most have been patern copied and are avalible from KONIG transformers in germany {use google}

with google you can type in whats on the label followed by lopt or flyback transformer

google has a manufacturers database and is the best at finding these parts




ill post more links as i remember them

but just to add to ident your lopt
as you will get one ....!!!


{oads of eeeeeeeee or the greenlight flashes or the monitor goes ehehehehehehe no picture possible lopt failure

a tv engineer will help you be sure that it is
if the monitor just trips
there is a transistor that dies called the Flyback oscillator Transistor

so it is usualy bolted to a heatsink
the classic fault is that the transistor gets too hot one day
and melts a little white disk that is normaly part of the isolation kit to keep the metal parts of the device from shorting to the heatsink

if it melts three things can happen appart from the transitor that can also be faulty

1} the monitor is dead but trips blimp blimp blimp and the green power led flashes this isnt always the transformer

2} load ringing noise goes away if you disconnect the frame driver coils and power the set up or disconnect the center of the flyback transistor {collector of the transistor drain of the fet {if its a fet}}
usualy means the transistor is dead {a warning look for a capacitor {blue or other box two pins sometimes these are mylar {red and shinny} or box type } that has become leeky
it may not be the lopt to blame
maybe a stage is drawing too much current from the lopt windings
NEVER just replace a lopt and fire at will
always look at what it also supplies with power as dry caps cause massive current to be drawn and will refry the coils again unless this is remidied also

3} the monitor powers up no ringing just a black screen even if the brightness if full
this is a classic lopt fault


some older monitors have a separate lopt and also a trippler unit
this can be replaced easier just three or four connections {its a green box usualy has a big fat red wire that goes to the top back of the tube
connecting witha big cap

this is the hot end 30KV so be carefull to discharge it using two insulated screewdrivers to the black stuff {graphite coating is earth}



if you have just a single white line accross the tube
turn the monitor off
you have a frame driver fault or the power supply to that stage has gone funny

this can also appear as a lopt fault
but realy its just a few dry caps and a safty resistor {low value usualy .33 .22 or .1 ohms }
maybe a blown chip


so further investigate your lopt fault before you condemn
ive had sets go round ten engineers
then i get a look and its a crack in the board or a large dry joint

or at worst a shorted capacitor that they missed is the real and only fault

my strong advice is try to use a local guy that knows monitors
tv engineers all watch neighbours
....to help you out

simbo

Postby simbo » Sat May 29, 2004 9:31 pm

When the SC1435 gets the "high pitch buzz, no picture", it's generally the output transformer.
I've got about 3 like this now.



hum not total rubbish but not 100% accurate

a load squeel can be had for several reasons

if its squeeling then there is a chance its just the transistor
if the flyback transformer
windings fry usualy it smells bad and tryes to go on fire

if the trippler in it dies {where the thick red wire comes from}
the monitor will mostly likly trip or power normaly with a black screen
and no "raster" like the static charge you get on the screen front
{this is the giveaway your lopt is ok if you get the static then its running } if you dont get static but it powers aok then you get no picture and a load crack every so often this is definatly the lopt

appart from this well
so your fault is most probably a few dry caps on the lt windings of the transformer
that has caused the transistor to overheat squeel and or fail or the vertical frame driver is short somewhere
or the psu has a fault or a cap is short on the ht {200v } supply to the trasistor from the psu

then the psu squeels becouse it dosnt detect the fault and trip
{the triping is detected becouse the timing is wrong between the lopt and the switchmode psu stage } so is never detected as a lopt fault
by the psu you see if the trippler dies in the lopt the set will carry on as normal
this leaves you with the windings are shorted or "cooked"
this is actualy quite hard to do
and usualy is just a simple diode ha shorted or other
or the psu would trip instead of squeel


this can also be caused by a leeky diode called a damper diode
most transistors have an integral one
but some it is also mounted on the board near the transistor
if it goes leeky the psu will labour and it will squeel


just as a short or low voltage rail and the powersupply labours to keep up hence the squeel


so try to fix them again
take the chassis completely out if you need to cut the black earth cut it and use a choc box {two screews use to connect domestic mains wires} one section when puting it back in

so hunt for other issues where too much current is drawn somewhere

before condemn the one part that realy hardly fails

and is super hard to find sometimes

if you take a picture and pm it too me of both sides of a chassis pcb
ill point out the fault

if you pm me a copy

User avatar
Ragstaff
Atari Super Hero
Atari Super Hero
Posts: 610
Joined: Mon Oct 20, 2003 3:39 am
Location: Melbourne Australia
Contact:

Postby Ragstaff » Sun May 30, 2004 12:39 am

Thanks for all that simbo, you're one extremely knowledgable bloke!

Thanks a lot for your offer of looking at the PCB - I will take a pic as soon as I can!
My monitor(s), are packed up in boxes at the moment as I've moved half-way across the country, so it may be a while before I get round to it.

As for my 50% rubbish statement, well I thought because I'd had a couple of monitors do the same thing it was the usual fault. Probably not the soundest of logic, but the problem described here was the same so I jumped the gun. Sorry about that :)

The symptoms my monitors have are:
    -black screen - no white line or static or anything. Looks like the cathode -gun is asleep at the back of the classroom :)
    -The power LED comes on as expected
    -There is a high-pitched buzzing sound
    -There is no cracking sound.



I can tell you what happened with one of them: I had the ST and monitor running off a single power-board that was powered by an extension chord running somewhere else in the house. Someone turned off the powerpoint that the exntension chord was plugged in to.
When I went and turned it back on, the monitor was dead. The ST worked fine, but the power LED flickered!!edit: the power LED on the >ST< I mean
Now, I assume it was not the power LED that was damaged, but something in the power supply?
Last edited by Ragstaff on Mon May 31, 2004 9:41 am, edited 1 time in total.

simbo

Postby simbo » Sun May 30, 2004 9:22 am

hum this sounds like the lopt :roll:
but may just be a cap gone short or a leeky damper diode
or lt windings
anyway at the links above is transformers that will work if needed
so as you say once your in a position to do something
get back too me and ill look see

perhaps is something simple a few tests will show

all you need is the number and youll get one if it is

good luck moving i just had to do the same


Social Media

     

Return to “Hardware”

Who is online

Users browsing this forum: No registered users and 3 guests