Oven LCD display dim and uneven

[GA Novice]

Re: Oven LCD display dim and uneven

The board has two levels. The bottom level has the caps, the top level has the display. The two boards are connected by a series of metal wires on one side. The solder side of the boards was difficult to access, I had to slowly pry the boards apart (bending the metal wires) to access the solder holes for the caps. Picture attached showing the inside of the two boards and the new caps installed. I didn't focus on the top level when I had it out. I found a picture of the top level on the internet and it is attached. It does not look like there are any big caps on the front, just two very small ones. Do you think those small ones could be the issue?

The attached picture has a very clear image of the display (not my actual display). The part of my display that is the weakest is the oven temp in the upper right corner. Looking at the picture, it looks like the oven temp is in 3 separate cells. So it must be the horizontal aspect of the display that is faulty. In a picture in my original post, the BAKE light is still ok, which is in the bottom of one of the cells of the oven temp. So I think the issue is the part of the VFD display that is horizontal. Time to do some VFD research.

I will add that this oven is hardly used. So although it is close to 20 years old, the oven temp is rarely illuminated. The clock is always on, and appears to be brighter than the oven temp, even though the clock has been illuminated for close to 20 years.

Thanks for any suggestions you may have.

[R_J]

Re: Oven LCD display dim and uneven

Are there any caps on the display board itself? It may use a small dc-dc converter circuit elsewere.

[GA Novice]

Re: Oven LCD display dim and uneven

I changed the caps and no dice, display is still uneven. Looks like the VFD is worn out. The old caps all tested good except the ESR was a little higher than the ESR of the new caps.

[GA Novice]

Re: Oven LCD display dim and uneven

Thanks for the comments. I am going to change the caps and see if that does it. Also, I realized this is in the wrong forum, it should be in the Other Wierd Devices, if a mod could move this there, thanks.

[Heihachi_73]

Re: Oven LCD display dim and uneven

Yeah, the cap date codes are from the year 2000, it's a safe bet that they starting to dry out, especially being next to that transformer and most likely operating 24/7. They look like Elna caps, which are a good brand, although any caps can fail when their time is up.

The display looks like a VFD (vacuum fluorescent display) rather than LCD or LED. They can also go dim over the years, although I had seen 1980s car dashboards where the VFD is still in good condition, as well as VCRs and stereo equipment of similar vintage.

[R_J]

Re: Oven LCD display dim and uneven

I would suspect the 50 volt caps would be for the display voltage which shouild be around 25-30 volts dc. or it could be the 3300 which is likely the main filter cap. Without a cap/esr meter to check them, I would just replace all of them, if that does'nt fix it it could be just the age of the display itself

[GA Novice]

I have an 18 year old Frigidaire range (combo oven and cooktop). The display (part number 316080102, no longer in production) is dim and uneven. It looks worse than in the picture. The red letters in the upper right of the display are particularly dim, this is where the temperature is displayed. I opened up the control panel and the caps do not have obvious tell tale signs of failure. There are 4 caps - 100uf 50v, two 470uf 16v and 3300uf 16v. Do you think the caps are bad (and if so which one), or is this a sign the LCD display is bad? Thanks for your thoughts. Pictures below.