Brionvega Doney 14" Color Issues - UK Vintage Radio Repair and Restoration Discussion Forum

ninehundreds · 24th May 2023, 2:30 pm

Hi,
I recently purchased a Brionvega Doney 14” CRT television, which I had shipped over to Canada from Italy. It’s the 2002 era model, with RF, SCART, and S-Video inputs, and it’s configured for the PAL region standard. During the unboxing, I discovered that the unit had a bumpy ride over the ocean. The power board had come loose from its holder, and a couple wire connections had also come loose. It also had a musty smell, so I knew this was going to be a project. In any case I reconnected the loose bits, gave it a quick visual inspection, and fired it up.

The unit worked flawlessly for a few days, and then I noticed that the color would drop out on the input signal (PAL signal through SCART connector), and come back intermittently. I was planning on disassembling it anyway to deal with the mold, so I took it apart completely and cleaned everything. I found a few poor solder joints which I reflowed, but otherwise everything visually looks fine. I also replaced the dried up thermal paste on the heatsink components.

After reassembling, it smells much better, but the problem with the color dropping out remains. I don’t have a schematic, which makes this much more difficult to diagnose. I saw some other folks with similar models have posted on here, and was hoping someone could point me in the right direction. It appears to use Phillips chips throughout, so nothing particularly unique. I can post photos of the boards and individual components if it’s helpful. I appreciate any insight the community has.

Maarten · 24th May 2023, 3:22 pm

If there's a trimming capacitor near the colour crystal (usually 4.43 or 8.86 MHz), this could be intermittent. Just note its position and give it a few turns and see if it makes any difference.

gallowfields · 24th May 2023, 7:32 pm

also if the chroma jungle i/c is fitted in a socket remove the socket and solder it in the pcb direct

ninehundreds · 24th May 2023, 11:43 pm

Thanks so much for the suggestions. I don’t see a trimmer capacitor on the board near the TDA-8842 IC, but I put the scope on pin 34 to verify the output of the crystal, and it’s jumping all over the place. It will bounce between 4.2 and 4.7MHz, which I'm guessing isn't great. I’m going to attempt to trace the circuit and test the component values next. I’ve attached a couple reference photos.

gallowfields · 25th May 2023, 7:42 pm

Have you got another 4.43MHz crystal to try?

ninehundreds · 26th May 2023, 2:21 am

Unfortunately not one with that specific frequency. I'm going to order a couple when I get a chance and will report back.

Welsh Anorak · 26th May 2023, 9:31 am

Most PAL decoders used that frequency crystal so if a new one's difficult to source an old TV should yield one.

ninehundreds · 26th May 2023, 1:17 pm

Quote:

Originally Posted by Welsh Anorak

Most PAL decoders used that frequency crystal so if a new one's difficult to source an old TV should yield one.

Those crystals are plentiful on Mouser. I've got a few on the way. Hoping the fix is that easy.

John123 · 28th May 2023, 1:18 am

In the meantime, if you have an RGB source to feed in via the SCART, this should bypass the decoder issue.

ninehundreds · 30th May 2023, 2:56 am

Unfortunately I don't have an RGB source. I soldered in the replacement crystal this evening, and initially got no colour at all. Then a few minutes later while I was getting ready to put the scope on it to check the crystal, there was an arc and I removed power. It looks like one of the NPN's let out the magic smoke, but it's difficult to tell at this point. Just some dark gray dust near the component, but no visible damage to anything. I'm going to keep at it a bit longer, but I may just look for someone local to diagnose and repair it, instead of playing whack-a-mole since I don't have a schematic. I'm sure this will be a lot clearer for someone with experience repairing TVs.

marceljack · 30th May 2023, 1:19 pm

Quote:

Originally Posted by ninehundreds

Unfortunately I don't have an RGB source.

Not even a DVD player, satellite or Freeview receiver with a SCART output ?

ninehundreds · 30th May 2023, 2:29 pm

Quote:

Originally Posted by marceljack

Quote:

Originally Posted by ninehundreds

Unfortunately I don't have an RGB source.

Not even a DVD player, satellite or Freeview receiver with a SCART output ?

No I'm in Canada....SCART isn't a thing here

24th May 2023, 2:30 pm	#1
ninehundreds Diode Join Date: Mar 2023 Location: Toronto, Canada. Posts: 6	Brionvega Doney 14" Color Issues Hi, I recently purchased a Brionvega Doney 14” CRT television, which I had shipped over to Canada from Italy. It’s the 2002 era model, with RF, SCART, and S-Video inputs, and it’s configured for the PAL region standard. During the unboxing, I discovered that the unit had a bumpy ride over the ocean. The power board had come loose from its holder, and a couple wire connections had also come loose. It also had a musty smell, so I knew this was going to be a project. In any case I reconnected the loose bits, gave it a quick visual inspection, and fired it up. The unit worked flawlessly for a few days, and then I noticed that the color would drop out on the input signal (PAL signal through SCART connector), and come back intermittently. I was planning on disassembling it anyway to deal with the mold, so I took it apart completely and cleaned everything. I found a few poor solder joints which I reflowed, but otherwise everything visually looks fine. I also replaced the dried up thermal paste on the heatsink components. After reassembling, it smells much better, but the problem with the color dropping out remains. I don’t have a schematic, which makes this much more difficult to diagnose. I saw some other folks with similar models have posted on here, and was hoping someone could point me in the right direction. It appears to use Phillips chips throughout, so nothing particularly unique. I can post photos of the boards and individual components if it’s helpful. I appreciate any insight the community has.

24th May 2023, 3:22 pm	#2
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,203	Re: Brionvega Doney 14" Color Issues If there's a trimming capacitor near the colour crystal (usually 4.43 or 8.86 MHz), this could be intermittent. Just note its position and give it a few turns and see if it makes any difference.

24th May 2023, 7:32 pm	#3
gallowfields Hexode Join Date: Feb 2018 Location: Durham, County Durham, UK. Posts: 325	Re: Brionvega Doney 14" Color Issues also if the chroma jungle i/c is fitted in a socket remove the socket and solder it in the pcb direct

24th May 2023, 11:43 pm	#4
ninehundreds Diode Join Date: Mar 2023 Location: Toronto, Canada. Posts: 6	Re: Brionvega Doney 14" Color Issues Thanks so much for the suggestions. I don’t see a trimmer capacitor on the board near the TDA-8842 IC, but I put the scope on pin 34 to verify the output of the crystal, and it’s jumping all over the place. It will bounce between 4.2 and 4.7MHz, which I'm guessing isn't great. I’m going to attempt to trace the circuit and test the component values next. I’ve attached a couple reference photos. Attached Thumbnails

25th May 2023, 7:42 pm	#5
gallowfields Hexode Join Date: Feb 2018 Location: Durham, County Durham, UK. Posts: 325	Re: Brionvega Doney 14" Color Issues Have you got another 4.43MHz crystal to try?

26th May 2023, 2:21 am	#6
ninehundreds Diode Join Date: Mar 2023 Location: Toronto, Canada. Posts: 6	Re: Brionvega Doney 14" Color Issues Unfortunately not one with that specific frequency. I'm going to order a couple when I get a chance and will report back.

26th May 2023, 9:31 am	#7
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,927	Re: Brionvega Doney 14" Color Issues Most PAL decoders used that frequency crystal so if a new one's difficult to source an old TV should yield one. __________________ Glyn www.gdelectronics.wales

28th May 2023, 1:18 am	#9
John123 Heptode Join Date: Jan 2007 Location: Luton, Bedfordshire, UK. Posts: 891	Re: Brionvega Doney 14" Color Issues In the meantime, if you have an RGB source to feed in via the SCART, this should bypass the decoder issue. __________________ Regards, John

30th May 2023, 2:56 am	#10
ninehundreds Diode Join Date: Mar 2023 Location: Toronto, Canada. Posts: 6	Re: Brionvega Doney 14" Color Issues Unfortunately I don't have an RGB source. I soldered in the replacement crystal this evening, and initially got no colour at all. Then a few minutes later while I was getting ready to put the scope on it to check the crystal, there was an arc and I removed power. It looks like one of the NPN's let out the magic smoke, but it's difficult to tell at this point. Just some dark gray dust near the component, but no visible damage to anything. I'm going to keep at it a bit longer, but I may just look for someone local to diagnose and repair it, instead of playing whack-a-mole since I don't have a schematic. I'm sure this will be a lot clearer for someone with experience repairing TVs.