Help needed in repairing Squeezebox Classic VFD

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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.
 
Nobody a clue?

I'm still waiting for some light into the matter.

In the mean time I've not stood still. I have 'mastered' net-udap which was brought to the Squeezebox community as a Perl-based tool to install the SB Receiver without needing a remote controller.

The tool works for a number of other SB's too. Normally there is no need to work with udap since all other SB's have screens to do what is needed. But not in my case where the screen has no power and refuses to shine.

I figured out how to feed all necessary settings into the Classic. I first made a script into a text-editor so that I could experiment easily. With copy and past I move all commands to the udap-tool, reset the Classic and in the end it worked.

Next I disabled the normal remote because this is confusing without screen.

Conclusion: now I have some kind of Duet-receiver without screen that looks at the outside like a Classic. It can be controlled with Iphone and Ipad etc.

But all ideas about getting the screen alive I welcome.
 
Hi rmgvs,

I had exactly same vfd supply problem, that I was thinking of fixing by replacing internal switcher with external supply(ies). But eventually I ended up fixing the internal power supply.

If you are still interested, I can send you the process, but I need to document it first.

Essentially I replaced the switching transistor, switching ic, and the filter cap. The ladder diodes were ok - can be verified easily with a multimeter.

The switching transistor in smps was blown. Hence I changed it -> it was blown up again. Then I searched for the switching ic, I think I got it from littlediode uk. Changed the IC - but no luck. Then I ripped off the condenser can (without damaging the pcb !) and replaced it with a through hole type capacitor - and that was it .... my sb3's vfd was shining bright again!

It all looks easy and straightforward now - but those were many long frustrated nights. I almost sat on that VFD issue for 5 months. I had even ripped of the VFD to check filaments!

Now I am the luckiest person on the earth - my sb3 just works fine that I have hooked up to a raspberry pi and the output is hooked to yamaha rx-z1 with yamaha mx-1000 for the front right and left channels.

I control SB3 using android phone(s) and also kindle fire HD.

The system sounds so great -- I had never achieved that audio quality in my life. (My first tube radio fix was about 30 years ago!)

Do let me know if you want photos and detailed explanation - but try it ONLY IF you are good at SMD (de)soldering.

-restoreman
 
Its the electrolytic cap 22uf 63v after the ladder. That dries out and then tripps the switching power supply. Try replacing the 22uf 63 v cap with normal through hole type if you u dont have surface mount type. I have two sb3s and i changed that cap on both.
 

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I know this is an old thread, but I have further information that might help others who experience this problem and find this thread...

Today I was faced with an SB3 with no display. The brightness button did nothing, but everything else worked (play, pause, etc), and it played my music.

I PM'd RepairMan, and he replied:
"It's the electrolytic cap 22uf 63v after the ladder. That dries out and then trips the switching power supply. Try replacing the 22uf 63 v cap with normal through hole type if you u don't have surface mount type. I have two sb3s and I changed that cap on both."

As it turned out, when I took the SB3 down to the workshop to look at repairing it, I tried it on a spare SB3 supply, and the display worked! So it seems with a faulty supply, everything might still work except the display.
So it was just a matter of replacing the plug-pack PS and all is hunky-dory again!

Daniel
 
Thanks for sharing restoreman, I have a SB classic v3 with the same symptoms, replaced the 22uf 63v cap with a through-hole version I found. Did not work unfortunately, which IC are the switching transistor and switching IC located? I'll try to replace them too.

Unfortunately I only have a simple multi-meter and a so-so soldering iron (it's a Weller but I can't change the temperature) so repairs like this are quite difficult.
 
Hello everyone,

I have a similar problem with Squeezebox 3. My display doesn't work at all but Squeezebox seems to work fine from squeezecenter and UDAP.
VFD 55 VDC voltage is present on the capacitor and display connector and display heats up as expected there is no any content, just blank display.
Can the display be damaged somehow during the transportation and how can I be sure that the display is damaged rather than other electronics that drives the display ?
 
I've had a few pieces of electronics with VFD displays get damaged in shipping. It was usually a simple fix (resoldering a few legs on the VFD and/or repairing some nearby traces). The VFD on the SB seems to be attached a bit more securely than many of the devices fro the 80s.

I have several SBs all over the house of various vintages (even a SliMP3 in the garage). The main VFD issue I have seen on the fancier SB3 displays is some burn-out from the clock. I always kept the brightness low, but they still have burnout after running for so many years. Thanks to restoreman for the info on the cap. I'll be looking out for that. Might be worth replacing before it takes out the switcher.

The main issue with SBs for me has been the power supply. About half of them have died or became so noisy (either EMI or "singers") that I had to toss them. Luckily they are just 5V supplies and use the same barrel connector as many older USB hubs. If the SB is acting wonky, try a different wall-wart. I built a linear supply for the one in my main system, but that is a bit overkill.

Good luck! Not too many pieces of streaming gear are still useful after so many years. These just work and the flexible backend keeps up with the times (I just got TIDAL up and running).
 
Thanks rknize for sharing your experience.
I already have tried several power supplies including one regulated laboratory PSU without success. In meantime, i checked AC voltage on scope and it is o.k. so the display have all power rails (55VDC, logic voltage and AC) presented.
Now I wonder to what other should I look at ? You mention re-soldering, but in my case all VFD display pads are soldered properly.
If I don't make any progress on display repairing I will focus on SB3 setup as a receiver controlled via smartphone. Unfortunately I didn't find any solutions how to use this device without PC workstation in the setup. In this case device must be connected to squeezebox cloud server, on my account so that I can use and control device (internet radio streaming) from any browser. Does anybody knows how to setup and register SB3 on cloud service without display and remote control ?!
 
Picked up a SB3 for $5 sans remote at Goodwill, No one even knew what it was until I googled it. It lit right up using a PSP power supply (5V 2A with the proper plug) but the darn dsaplay died about 5 hours into configuring it with a universal remote emulating a JVC DVD. IIRC the PS failed and maybe it shorted the SB3 board? I do have a red SPDIF socket and I have 5V everywhere plus a few 3.3 and 1.2V so I believe the board is still good its just the VFD. I replaced the PS, the 22uf/64V cap with a 22uf/100V I had in the parts bin, no change. I have no voltage over 5V into the display. Large cap has 4.5v in.
 
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