Picture Barreling - Philips Matchline Model 28PW9525-05L - UK Vintage Radio Repair and Restoration Discussion Forum

JohnMWWarks · 26th Feb 2016, 8:42 am

Hi there

I have a Philips Matchline Model 28PW9525-05L, which I believe uses the chassis MG2.1E, MG3.1E, MG4.1E, MG7.1E. I also have a schematic circuit diagram for this TV.

The set works just fine once it has warmed up, however when you first turn it on there is some "Picture Barrelling", so any vertical objects in a picture look distinctly curved. Once the set has warmed up this disappears and everything
is OK.

The question is where on the circuit diagram should I be looking to correct this. The fault is most noticeable when watching something like GOLD TV were a lot of content was made in the 4:3 format so you get a square rather than rectangular picture. With this fault the picture appears curved vertically, so the straight black areas down each side are well not straight.

Has anyone got any ideas what can be done to cure this fault or know anyone preferably in the Warwickshire area who can take a look at it ?

Thanks JW

Welsh Anorak · 26th Feb 2016, 2:54 pm

Hi there
Does the fault cure itself gradually or just 'snap' to the correct shape? If the latter a dry joint will be to blame; the former would point to a faulty capacitor in the E/W correction circuit. Unfortunately I'm a bit far away from you to look at it!
Glyn

JohnMWWarks · 26th Feb 2016, 8:04 pm

It snaps to the correct shape Glynn. I'm just wondering where to look on the schematic.

Welsh Anorak · 27th Feb 2016, 12:19 pm

It's the E/W correction circuit that needs looking at. Of course it's a Philips, so the manual is a bit convoluted with all the different variants. I'd have a look at the circuit board with a magnifier and see if there are any dry-joints on the wound components in this circuit - I think there are two or three. Check the big yellow capacitors if there are any as they can fail like this. Also check for dry-joints on the E/W correction transistor itself. I don't have the manual in front of me, but if you're still in trouble I'll dig it out and have a look for you.
Glyn

26th Feb 2016, 8:42 am	#1
JohnMWWarks Retired Dormant Member Join Date: Feb 2016 Location: Warwickshire, UK. Posts: 2	Picture Barreling - Philips Matchline Model 28PW9525-05L Hi there I have a Philips Matchline Model 28PW9525-05L, which I believe uses the chassis MG2.1E, MG3.1E, MG4.1E, MG7.1E. I also have a schematic circuit diagram for this TV. The set works just fine once it has warmed up, however when you first turn it on there is some "Picture Barrelling", so any vertical objects in a picture look distinctly curved. Once the set has warmed up this disappears and everything is OK. The question is where on the circuit diagram should I be looking to correct this. The fault is most noticeable when watching something like GOLD TV were a lot of content was made in the 4:3 format so you get a square rather than rectangular picture. With this fault the picture appears curved vertically, so the straight black areas down each side are well not straight. Has anyone got any ideas what can be done to cure this fault or know anyone preferably in the Warwickshire area who can take a look at it ? Thanks JW Attached Thumbnails

26th Feb 2016, 2:54 pm	#2
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,921	Re: Picture Barreling - Philips Matchline Model 28PW9525-05L Hi there Does the fault cure itself gradually or just 'snap' to the correct shape? If the latter a dry joint will be to blame; the former would point to a faulty capacitor in the E/W correction circuit. Unfortunately I'm a bit far away from you to look at it! Glyn

26th Feb 2016, 8:04 pm	#3
JohnMWWarks Retired Dormant Member Join Date: Feb 2016 Location: Warwickshire, UK. Posts: 2	Re: Picture Barreling - Philips Matchline Model 28PW9525-05L It snaps to the correct shape Glynn. I'm just wondering where to look on the schematic.

27th Feb 2016, 12:19 pm	#4
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,921	Re: Picture Barreling - Philips Matchline Model 28PW9525-05L It's the E/W correction circuit that needs looking at. Of course it's a Philips, so the manual is a bit convoluted with all the different variants. I'd have a look at the circuit board with a magnifier and see if there are any dry-joints on the wound components in this circuit - I think there are two or three. Check the big yellow capacitors if there are any as they can fail like this. Also check for dry-joints on the E/W correction transistor itself. I don't have the manual in front of me, but if you're still in trouble I'll dig it out and have a look for you. Glyn