Acorn Electron problem flashing picture and lines

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traindriver69
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Acorn Electron problem flashing picture and lines

Post by traindriver69 » Wed Jul 08, 2020 6:59 pm

Hi all
Now got my plus 3 sorted need to fix my electron everything works but just on the screen I get like interference with flashing lines like someone is moving a loose areial lead around I get through rf and video not tried rgb as I dont have a lead.
sometimes it stops for a few secs then goes like mad .
any help please.

traindriver69
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Re: Acorm Electron problem flashing picture and lines

Post by traindriver69 » Thu Jul 09, 2020 9:53 am

Hi all
Heres a quick video atachment of what it is doing any help please.
Attachments
electron.mp4
(4.76 MiB) Downloaded 25 times

Kazzie
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Re: Acorm Electron problem flashing picture and lines

Post by Kazzie » Thu Jul 09, 2020 10:03 am

From the video footage, I'd agree that it looks like a poor connection in the RF cable, or at one of the ends.

Have you tried the Electron and lead with another TV? If there's no change, I'd suggest trying a replacement lead.
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traindriver69
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Re: Acorm Electron problem flashing picture and lines

Post by traindriver69 » Thu Jul 09, 2020 10:18 am

Hi
problem is I get the same through the video connection with a phono lead.

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Re: Acorm Electron problem flashing picture and lines

Post by mark71 » Thu Jul 09, 2020 12:25 pm

traindriver69 wrote:
Thu Jul 09, 2020 10:18 am
Hi
problem is I get the same through the video connection with a phono lead.
Have you tried a RGB to Scart lead?

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roland
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Re: Acorm Electron problem flashing picture and lines

Post by roland » Thu Jul 09, 2020 12:26 pm

Did you already clean the pins of the ULA? That is a common component for both video and UHF output.
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traindriver69
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Re: Acorm Electron problem flashing picture and lines

Post by traindriver69 » Fri Jul 10, 2020 11:41 am

Hi
no I have not what is the best way of doing it do I just clean the pins where it is or do I have to remove the ula and clean the lot.

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daveejhitchins
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Re: Acorm Electron problem flashing picture and lines

Post by daveejhitchins » Fri Jul 10, 2020 12:07 pm

traindriver69 wrote:
Fri Jul 10, 2020 11:41 am
Hi
no I have not what is the best way of doing it do I just clean the pins where it is or do I have to remove the ula and clean the lot.
You can only do this if your ULA is in a socket (Issue 6 boards are a different type of ULA build!).

So, assuming you have a socketed ULA then you need to remove the clip that hold the ULA in place. There are two main ULA sockets - the more common socket is easier and is more likely to suffer broken pins. If you are unsure post a photo and better guidance can be given!

Once you have removed the retaining clip - remove the ULA and clean the pins carefully with IPA on a cotton bud (don't leave cotton in there!) or a small brush. You can also clean the gold contacts of the ULA with IPA and cotton bud.

Replace retaining lid. Then, while you're in there . . . Remove the whole PCB and clean the rear edge connector - this won't fix your current problem, however, will reduce any future issues!

Dave H :D

traindriver69
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Re: Acorm Electron problem flashing picture and lines

Post by traindriver69 » Fri Jul 10, 2020 12:43 pm

Hi
This is what I have
IMG_20200710_124212.jpg

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jms2
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Re: Acorm Electron problem flashing picture and lines

Post by jms2 » Fri Jul 10, 2020 1:13 pm

That’s an issue 4. You need to ease the metal clip thing off, after which the ULA simply lifts out. Take care with the pins, they are tiny springs and so you don’t want to snag them with cotton wool. Personally I’d only clean the flat pads under the ULA itself.

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daveejhitchins
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Re: Acorm Electron problem flashing picture and lines

Post by daveejhitchins » Fri Jul 10, 2020 1:17 pm

traindriver69 wrote:
Fri Jul 10, 2020 12:43 pm
Hi
This is what I haveIMG_20200710_124212.jpg
If you can't figure out how to release the clamp, do let us know and I'll do a few photos.

Dave H :D

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Re: Acorn Electron problem flashing picture and lines

Post by dixiestoat » Fri Jul 10, 2020 5:03 pm

I thought that ULA was only on Issue 2, and Issue 4's had the Metal Top Springy Clip... for want of a better description.. :lol: Obviously not..!
If in doubt, CTRL-BREAK thou should clout..

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Re: Acorn Electron problem flashing picture and lines

Post by traindriver69 » Fri Jul 10, 2020 6:43 pm

Hi
If you could supply some pics just to be sure that would be brilliant I have only got the one electron and don't want to cock it up.

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jms2
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Re: Acorn Electron problem flashing picture and lines

Post by jms2 » Fri Jul 10, 2020 7:15 pm

I plan to open up my issue 4 hopefully this weekend to clean the ULA pads so if there are no existing pictures I will post some.

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daveejhitchins
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Re: Acorn Electron problem flashing picture and lines

Post by daveejhitchins » Fri Jul 10, 2020 8:27 pm

traindriver69 wrote:
Fri Jul 10, 2020 6:43 pm
Hi
If you could supply some pics just to be sure that would be brilliant I have only got the one electron and don't want to cock it up.
I'll get some photos for you tomorrow . . .

Dave H :D

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Re: Acorn Electron problem flashing picture and lines

Post by traindriver69 » Sun Jul 12, 2020 10:49 am

Hi
Any chance of some pics on removing the ULA please don't really want to cause any damage to it.
Many Thanks

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Re: Acorn Electron problem flashing picture and lines

Post by jms2 » Sun Jul 12, 2020 2:33 pm

Sorry I haven’t had a chance to get mine apart yet. Not forgotten though.

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Re: Acorn Electron problem flashing picture and lines

Post by jms2 » Sun Jul 12, 2020 6:48 pm

OK, done it now, here are some pictures:

First thing to note is that the hold-down clip is different on yours compared to mine. However the socket looks the same, so I think the same basic principles should apply. The H shaped clip is spring-loaded and has four legs which hook under the four corners.
IMG_3264.JPG
The basic technique is to use something sharp to get behind each leg, and while pushing down to unhook it underneath, push gently outwards and then release the downwards pressure. This allows it to unhook.
IMG_3265.JPG
Here are two legs unhooked.
IMG_3266.JPG
At this point you can ease up one side but you still need to undertake the unhooking process for the other side.
IMG_3267.JPG
Unhooking the other side:
IMG_3268.JPG
This is the clip removed:
IMG_3270.JPG
At this point there is nothing holding the ULA down other than gravity:
IMG_3271.JPG
You can simply lift it out, don't worry about putting it back the wrong way because its keyed:
IMG_3272.JPG
This is the inside of the socket. All the little contacts are spring loaded.
IMG_3273.JPG
IMG_3273.JPG
Attachments
IMG_3269.JPG

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jms2
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Re: Acorn Electron problem flashing picture and lines

Post by jms2 » Sun Jul 12, 2020 6:53 pm

This is the underside of the ULA showing the pads. They are not vulnerable at all (no spring loading here):
IMG_3274.JPG
I would suggest gently scraping the tops of the socket contacts with a metal object, rather than touch them with a cotton bud. I guess you could wipe them with a piece of paper soaked in IPA (not India Pale Ale!):
IMG_3277.JPG
Here's the IPA/paper technique used on the ULA contacts. You can "scrub" a bit.
IMG_3279.JPG
When putting the clip back, the front side has special "ramps" to aid in pressing down the clip. So you need to hook on the back side first.
IMG_3281.JPG
Then press down the front. It's easier to do one corner at a time.
IMG_3282.JPG

traindriver69
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Re: Acorn Electron problem flashing picture and lines

Post by traindriver69 » Sun Jul 12, 2020 7:24 pm

Hi
That is brilliant and well described many thanks will let you know how I get on.

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jms2
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Re: Acorn Electron problem flashing picture and lines

Post by jms2 » Sun Jul 12, 2020 7:50 pm

I have never found any actual "dirt" on mine!

At the moment the keyboard is doing odd things, and it's not a keyswitch issue, so I think it must be down to the ULA. I cleaned it about a year ago and the problem went away, so I think I need to do it again.

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Re: Acorn Electron problem flashing picture and lines

Post by jms2 » Sun Jul 12, 2020 9:01 pm

My latest cleaning operation seems to have been successful - keyboard is now working nicely again!

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Re: Acorn Electron problem flashing picture and lines

Post by traindriver69 » Mon Jul 13, 2020 10:10 am

Hi all
I have taken the ULA out this morning and gave it a clean and now no more flashing screen brilliant many many thanks for your help.

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Re: Acorn Electron problem flashing picture and lines

Post by jms2 » Mon Jul 13, 2020 12:29 pm

Wow, I have to say that I was slightly doubtful that it would fix the problem, so it's great to hear that it did. My doubt came from the fact that I don't recall anyone else having a similar problem in the past.

Out of interest, did you find any visible dirt?

traindriver69
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Re: Acorn Electron problem flashing picture and lines

Post by traindriver69 » Mon Jul 13, 2020 1:20 pm

Hi
no it looked fine I wonder if the ULA just wanted reseating.

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Re: Acorn Electron problem flashing picture and lines

Post by Kazzie » Mon Jul 13, 2020 1:59 pm

Quite possible. Either way, the problem's gone. =D>
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Re: Acorn Electron problem flashing picture and lines

Post by daveejhitchins » Tue Jul 14, 2020 1:17 pm

Thanks for stepping-in, John - I've had a rather busy weekend.

Dave H :D

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