voltmeter for HT bench supply

[decowoodie]

I'm currently making a multi-output 'eliminator' supply for battery radios, all linear of course for RFI reasons.

I'd like some digital voltmeters for bias, HT and screen outputs. 
I ordered some from ebay and later aliexpress, which were rated 0-30V, 3-digit, for very little money (around a pound each).
I intended to use a multiplier to scale them to read 0-300V...but no luck. They're all auto-ranging, so for example 22V reads '22.0', 100V reads '100.' and 5V reads  '05.0' so a multiplier or potentiometer reducer won't do.
They use a 5V auxilliary psu so they read right down to 0V.

Any suggestions where I can get some suitable ones? I've already cut the panel out for the autoranging ones. 

(below are the ones I have, albeit the pic shows the 2-wire version).

   

[BusyBee]

Obviously a bit more expensive and a little programming needed but you could use an Arduino with either a led or LCD display. The LCD, particularly, is readily interfaced and obtains it's power from the Arduino. All it would require would be input divider circuitry and protection plus 5V supply. That way you could get whatever display you required.

Tracy

[Doodlebug]

AS its for battery sets if old I would prefer the good old analogue voltmeters one can buy on ebay. I'm old fashion :-)

[PerdioPal]

Use a 10:1 attenuator and label it decavolts? Much as I hate non x3 suffixes or prefixes

[Kalee20]

Can't you use moving-coil meters? There are some fairly cheap Chinese ones on ebay - I used three for a very similar project (that's tied up right now running a life test on Russian rod pentodes). Although I use external DMM's for accurate measurements, they're quite adequate for indication, and are easy to re-scale.

Photo shows a Work In Progress view of my front panel.

[decowoodie]

I just dont have space for anything bigger than these, I have to get 3 on a busy panel and already mounted them before realizing they're auto-ranging.
So I can't use a multiplier or potentiometer as they simply re-range as we go up and down.
They were advertised as 0-30V DC but at 3V they show '3.00' and at 30V they show '30.0'

[Kalee20]

Bum! I see your dilemma... you can't get the thing right for 30 - 300V.

Are there any links to disable the autoranging, and maybe snip out a decimal point? I had to butcher a cheap counter module last year (multiplexed display), adding a drive transistor - it worked!