Bush BTV183DVD/A frame collapse - UK Vintage Radio Repair and Restoration Discussion Forum

mark pirate · 21st Jun 2021, 4:07 pm

This set has not been used for a few years, on power up it all seemed fine, but then the picture became jerky & lost vertical size before just displaying a line across the screen.

I tried it a few days later, and got a repeat performance, I have checked the larger caps in the frame section, both tested fine for both value & ESR, but were subbed out anyway, but same problem.
The frame output chip is a TDA 8174A, this shows no sign of damage or overheating.

The set is made by orion and has a VHS & DVD player built in, so I think worth repairing, any ideas to what could be causing problem?

Mark

agardiner · 21st Jun 2021, 4:29 pm

Have you checked for dry joints around the LOPT etc? The frame derives it power supply from a sub supply off the LOPT, and dry's were common on these and similar sets.

Otherwise, I would replace the output IC as the next step; could be overheating and shutting down.

Welsh Anorak · 21st Jun 2021, 4:33 pm

Well, the obvious is a dry joint on the IC or the feed from the LOPTx but I'm sure you've checked that. If possible see if you are able to measure the voltages to the IC under fault conditions- you may well need to attach temporary test points wires to do that.
Then I'd change the IC - and if it doesn't work panic! Freezer and a hairdryer may be your friends here. ISTR a green capacitor in the frame generation circuit giving this fault on an Orion chassis back in the day, but only once.

Post crossed - great minds?

mark pirate · 21st Jun 2021, 4:53 pm

No dry joints that I can see, but reflowed both the LOPT & O/P chip.
The set was working perfectly prior to being unused for a few years, hence why I was thinking it could be capacitor failure.

Mark

Lloyd 1985 · 21st Jun 2021, 5:03 pm

Resistor going open circuit as it warms up?! If you get really stuck I’ve got the entire guts of one of these knocking about in storage! I was given 3 of them, one had obviously taken a tumble (or been thrown across the room because a DVD got stuck in it!) and the tube was smashed, it did work with a replacement tube, but I was thinning down during a house move so I gutted it and binned the case, and now it takes up more room than it did when it was complete! Don’t know when I’ll get to the lock up, it’s in Daventry, over 100 miles away! I was going to sort it out last year, but we all know what happened...

Regards
Lloyd

mark pirate · 21st Jun 2021, 5:11 pm

Quote:

but I was thinning down during a house move so I gutted it and binned the case, and now it takes up more room than it did when it was complete!

I am doing the same, I have already dumped loads of sets, but this one was one I was planning on keeping, I have had a look through my spares, but don't have a replacement chip

Mark

MickMcmichael · 21st Jun 2021, 5:37 pm

Hi Mark

If you PM me your address I have a new unused TDA8174A you can have.

Cheers,

Mick.

mark pirate · 21st Jun 2021, 6:23 pm

Many thanks Mick, PM on it's way.

Mark

Welsh Anorak · 22nd Jun 2021, 11:15 am

When I first saw the heading I thought it was one of my favourite old black and white TVs, the Bush TV183D!

mark pirate · 23rd Jun 2021, 7:10 pm

Mick very kindly sent me a new frame chip, but the results are the same, I even reflowed the frame section, just in case.

I still think it could be capacitor related, as I get a full raster when first switched on after being unplugged for a day, then it jumps down to about 2", then total collapse.

Mark

gallowfields · 23rd Jun 2021, 7:37 pm

seem to remember having frame problems that was down to poor connections on the scan coil plug and socket ,even hard wired some .

HamishBoxer · 23rd Jun 2021, 7:44 pm

Does the frame chip have a supply or is there an o/c safety res failed ?

mark pirate · 24th Jun 2021, 7:22 am

I have checked the connections to the scan coils, no problems found.
I will change out the remaining small electrolytics & check all resistors.
I have reflowed the entire frame section, so can rule out any dry joints.

Mark

HamishBoxer · 24th Jun 2021, 8:00 am

Is there voltage on the frame chip?

Welsh Anorak · 24th Jun 2021, 10:05 am

I'd do as suggested and hang a meter on the feed pin(s) of the chip. If they remain steady or rise slightly when the fault is there then I'd turn my attention to the frame generator stage.As I said earlier, I seem to remember an awkward fault like this on an Orion chassis was due to a small (non-electrolytic) in this stage. You might need the diagram.

G6ONEDave · 24th Jun 2021, 10:16 am

Might be worth checking that the 'sync chip' has got it's supply, often 12v from the mains psu. Also check all the rectifier diodes in the psu secondary for dry joints as well as checking output voltages from them. It's not uncommon for a diode to go short or leaky, which then removes a supply voltage.

Dave

agardiner · 24th Jun 2021, 1:48 pm

Keep looking for the obvious first with the various suggestions from others.... Voltage remaining on the frame IC, sync pulse etc.

However - I do seem to remember a batch of this chassis which suffered from the scan coils failing as they warmed up.

21st Jun 2021, 4:07 pm	#1
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Bush BTV183DVD/A frame collapse This set has not been used for a few years, on power up it all seemed fine, but then the picture became jerky & lost vertical size before just displaying a line across the screen. I tried it a few days later, and got a repeat performance, I have checked the larger caps in the frame section, both tested fine for both value & ESR, but were subbed out anyway, but same problem. The frame output chip is a TDA 8174A, this shows no sign of damage or overheating. The set is made by orion and has a VHS & DVD player built in, so I think worth repairing, any ideas to what could be causing problem? Mark Attached Thumbnails

21st Jun 2021, 4:29 pm	#2
agardiner Octode Join Date: Sep 2020 Location: Thetford, Norfolk, UK. Posts: 1,741	Re: Bush BTV183DVD/A frame collapse Have you checked for dry joints around the LOPT etc? The frame derives it power supply from a sub supply off the LOPT, and dry's were common on these and similar sets. Otherwise, I would replace the output IC as the next step; could be overheating and shutting down.

21st Jun 2021, 4:33 pm	#3
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,918	Re: Bush BTV183DVD/A frame collapse Well, the obvious is a dry joint on the IC or the feed from the LOPTx but I'm sure you've checked that. If possible see if you are able to measure the voltages to the IC under fault conditions- you may well need to attach temporary test points wires to do that. Then I'd change the IC - and if it doesn't work panic! Freezer and a hairdryer may be your friends here. ISTR a green capacitor in the frame generation circuit giving this fault on an Orion chassis back in the day, but only once. Post crossed - great minds? __________________ Glyn www.gdelectronics.wales

21st Jun 2021, 4:53 pm	#4
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Bush BTV183DVD/A frame collapse No dry joints that I can see, but reflowed both the LOPT & O/P chip. The set was working perfectly prior to being unused for a few years, hence why I was thinking it could be capacitor failure. Mark

21st Jun 2021, 5:03 pm	#5
Lloyd 1985 Nonode Join Date: Jun 2008 Location: Coningsby, Lincolnshire, UK. Posts: 2,819	Re: Bush BTV183DVD/A frame collapse Resistor going open circuit as it warms up?! If you get really stuck I’ve got the entire guts of one of these knocking about in storage! I was given 3 of them, one had obviously taken a tumble (or been thrown across the room because a DVD got stuck in it!) and the tube was smashed, it did work with a replacement tube, but I was thinning down during a house move so I gutted it and binned the case, and now it takes up more room than it did when it was complete! Don’t know when I’ll get to the lock up, it’s in Daventry, over 100 miles away! I was going to sort it out last year, but we all know what happened... Regards Lloyd

21st Jun 2021, 5:37 pm	#7
MickMcmichael Pentode Join Date: Mar 2009 Location: Peterborough, Cambridgeshire, UK. Posts: 196	Re: Bush BTV183DVD/A frame collapse Hi Mark If you PM me your address I have a new unused TDA8174A you can have. Cheers, Mick.

21st Jun 2021, 6:23 pm	#8
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Bush BTV183DVD/A frame collapse Many thanks Mick, PM on it's way. Mark

22nd Jun 2021, 11:15 am	#9
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,918	Re: Bush BTV183DVD/A frame collapse When I first saw the heading I thought it was one of my favourite old black and white TVs, the Bush TV183D! __________________ Glyn www.gdelectronics.wales

23rd Jun 2021, 7:10 pm	#10
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Bush BTV183DVD/A frame collapse Mick very kindly sent me a new frame chip, but the results are the same, I even reflowed the frame section, just in case. I still think it could be capacitor related, as I get a full raster when first switched on after being unplugged for a day, then it jumps down to about 2", then total collapse. Mark

23rd Jun 2021, 7:37 pm	#11
gallowfields Hexode Join Date: Feb 2018 Location: Durham, County Durham, UK. Posts: 325	Re: Bush BTV183DVD/A frame collapse seem to remember having frame problems that was down to poor connections on the scan coil plug and socket ,even hard wired some .

23rd Jun 2021, 7:44 pm	#12
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,932	Re: Bush BTV183DVD/A frame collapse Does the frame chip have a supply or is there an o/c safety res failed ? __________________ G8JET BVWS Archivist and Member V.M.A.R.S

24th Jun 2021, 7:22 am	#13
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Bush BTV183DVD/A frame collapse I have checked the connections to the scan coils, no problems found. I will change out the remaining small electrolytics & check all resistors. I have reflowed the entire frame section, so can rule out any dry joints. Mark

24th Jun 2021, 8:00 am	#14
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,932	Re: Bush BTV183DVD/A frame collapse Is there voltage on the frame chip? __________________ G8JET BVWS Archivist and Member V.M.A.R.S

24th Jun 2021, 10:05 am	#15
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,918	Re: Bush BTV183DVD/A frame collapse I'd do as suggested and hang a meter on the feed pin(s) of the chip. If they remain steady or rise slightly when the fault is there then I'd turn my attention to the frame generator stage.As I said earlier, I seem to remember an awkward fault like this on an Orion chassis was due to a small (non-electrolytic) in this stage. You might need the diagram. __________________ Glyn www.gdelectronics.wales

24th Jun 2021, 10:16 am	#16
G6ONEDave Octode Join Date: Dec 2019 Location: Owston Ferry, North Lincolnshire, UK. Posts: 1,701	Re: Bush BTV183DVD/A frame collapse Might be worth checking that the 'sync chip' has got it's supply, often 12v from the mains psu. Also check all the rectifier diodes in the psu secondary for dry joints as well as checking output voltages from them. It's not uncommon for a diode to go short or leaky, which then removes a supply voltage. Dave __________________ Quote "All is hyperthetical, until it isn't!" (President Laura Roslin, Battlestar Galactica)

24th Jun 2021, 1:48 pm	#17
agardiner Octode Join Date: Sep 2020 Location: Thetford, Norfolk, UK. Posts: 1,741	Re: Bush BTV183DVD/A frame collapse Keep looking for the obvious first with the various suggestions from others.... Voltage remaining on the frame IC, sync pulse etc. However - I do seem to remember a batch of this chassis which suffered from the scan coils failing as they warmed up.