Help needed in repairing Classic VFD

[rmgvs]

My question is simple and complex at the same time. I have spent several days searching on the internet and not found what I looked for.

It is about a Squeezebox Classic (V3 etcetera). Everything works fine except for the VFD display. I can pretty sure point to what causes the non-functioning of the display but am not able to pinpoint it to the exact location on the pcb (due to a lack of circuit diagrams for the V3, a shame since the player is not longer sold anymore, nor repaired for that matter, it seems like the SB's are seen as throw-away articles ...).

Sean Adams has made a block diagram of the different voltages of the SB3. It starts with the external powerplug (switched 5V). Inside this delivers 3v3 and 1v2 for IO, wireless, logic, CPU and headphone.

After the 5V it goes to a switcher and a multiplier too, where 11 VAC and 55 VDC are 'made' for the display and 14 VDC for the opamps and DAC. All these voltages are not available in my SB3 (I know what causes the failure but skip this for brevity).

It's easy to make a new 14 VDC for the opamp and DAC. There is one resistor of 100 Ohms (R45 on my pcb): take this out and apply an external 12-14 Volts at the big cap J2 and done. I'm amazed that this mod is not done more often by audiophiles. It has to be much better than all those expensive regulated 5V power supplies at the outside because anyhow after that there will be another switched component and other maybe no so audiophile stuff.

So after that everthing works as should except for the display. Now two options are open:

1. I can make another external power supply that delevers 11 VAC and 55 VDC. Question: which pins of the VFD are for what voltages? And: is there a simple circuit available that delivers both voltages starting from a small 12 vac transformer (ie some kind of Cockcroft-Whalton circuit that already had been used in the existing circuit)?

2. (This is the preferable option) I don't know where to start. The VFD is allright. It's only about the supply of proper voltages. Because the initial 5V is allright, the problem has to be in the internal switcher and/or the voltage multiplier (and/or in a connecting component for example a resistor that connects the stages). So (after 6 years of existence and ten thousand hours of worldwide modding these things) who can tell me which component on the board is the switcher and which is the multiplier (this must be the string of diodes D9-D13 with associated caps?). And what is the most probable component of break down due to a temporary burst in (too much) current?

Thinking along with me will be appreciated. These SB's are way too good to throw away after 3-5 years of operation. Help keeping the Classics alive!

[slimhase]

Hi:
I have a SB3, which works via digital output, but not via analog output.
I did some measuring and I think the 3.3V regulator for the BurrBrown DAC is faulty -> not giving 3.3V.
I have 2 questions:
1) Where can I buy this chip (ZXCL330 - marked as L33B) in Europe (w/o paying 10 Euros for shipping for a 20 cent item...)?
2) Does anyone still have the quoted diagrams from Sean Adams? I could try to use a different 3.3V Supply within the SB to verify that I am looking at the right area to repair my SB......

Thanks for your help!!

My question is simple and complex at the same time.....
Sean Adams has made a block diagram of the different voltages of the SB3. It starts with the external powerplug (switched 5V). Inside this delivers 3v3 and 1v2 for IO, wireless, logic, CPU and headphone.
.....
Thinking along with me will be appreciated. These SB's are way too good to throw away after 3-5 years of operation. Help keeping the Classics alive!

[Atlantic]

Everything works fine except for the VFD display. I can pretty sure point to what causes the non-functioning of the display but am not able to pinpoint it to the exact location on the pcb (due to a lack of circuit diagrams for the V3 [...]).

I am sure you have found these but, in case not, there is some VFD info here:

http://downloads.slimdevices.com/dat...25SCPB-U1J.pdf

The parent page

http://downloads.slimdevices.com/

also seems to link to other, related, info.

Perhaps this gives some clues, good luck,

Atlantic

[Craig]

I have a similar problem with the display fading away on some older Squeezeboxes,
does anyone know if this is caused by the VFD itself or some other component that can be replaced?

Thanks
Craig

[JJZolx]

I have a similar problem with the display fading away on some older Squeezeboxes,
does anyone know if this is caused by the VFD itself or some other component that can be replaced?

Is it uniform or more pronounced in certain areas such as the center of the screen? I have an SB2 that is burned out in the center from having used the date/time 'screensaver' at too bright of a setting for too long. In this case it's definitely wear on the VFD that is the problem.

There seem to be more and more broken SB2/3/Classics being sold for parts these days, from which I'd guess you'd have a good chance of salvaging a good VFD.

[Craig]

Well I have seen the shadowy effect you're talking about, this one seems to be getting dimmer overall.
It's an old SB1 but it's built in to a cupboard so the later shape players wouldn't suit.
I'll have a trawl for used displays though, I'm guessing it was the same one up to the Classic.

Craig

[azinck3]

Well I have seen the shadowy effect you're talking about, this one seems to be getting dimmer overall.
It's an old SB1 but it's built in to a cupboard so the later shape players wouldn't suit.
I'll have a trawl for used displays though, I'm guessing it was the same one up to the Classic.

Craig

The SB2 and SB3 (Classic) use a display that's the same physical size as the SB1/1g but with a different resolution. Is yours an SB1 or SB1g?

[JJZolx]

Well I have seen the shadowy effect you're talking about, this one seems to be getting dimmer overall.
It's an old SB1 but it's built in to a cupboard so the later shape players wouldn't suit.

The SB2 is housed in the same size and shape case as the SB1, plus it has many advantages, such as a much larger buffer which makes it more robust and immune to dropouts. With the demise of the Squeezebox line I'm sure we're going to be seeing many more old Squeezeboxes on the used market for pennies on the dollar. As has been discussed here (to exhaustion) there's no reason those Squeezeboxes won't continue to work for years, yet that's the way people think.

[Craig]

The SB2 and SB3 (Classic) use a display that's the same physical size as the SB1/1g but with a different resolution. Is yours an SB1 or SB1g?

It's a SB1G

Craig

[joejvj]

Here's some info on how to replace a faulty SB2 display