Tangent Amp - problem with display

[coojoe_213]

Hi. I have AMP-50 which work perfect put there is no light on display. There is three regulators for voltage 7805, 7808,7908. On 7805 i have 7.1, on 7808 i have 11.71v, on 7908 i have -12.04v . I see on the display everything but not light. Any suggestion?

[Agent24]

Re: Tangent Amp - problem with display

Those voltages are weird. Please verify you are measuring from the incorrect ground point and that your multimeter has a fresh battery.

Also, please upload some photos of the amplifier, especially the circuitry around the display section!

[R_J]

Re: Tangent Amp - problem with display

I found this link http://www.ziva-vatra.com/index.php?...d=SGFyZHdhcmU=
It looks like it is an lcd with the light source from the side, I suspect its one of those sheets that light up behind the display

[coojoe_213]

Re: Tangent Amp - problem with display

Yes, i know this link, but the person who mod his amp, doesn't have my problem. I have another question. If bulb on display is blow, can i change or no?

[stj]

Re: Tangent Amp - problem with display

i think those meter readings are the inputs - not the outputs.

[stj]

Re: Tangent Amp - problem with display

pull the display assembly out and show foto's

i know the pdf says "VFD", but it's clearly not - it's a self-contained display module with it's own driver circuits in it.
infact looking at the schematic i wouldnt be surprised if it's an LCD with a Hitachi parallel interface.

[coojoe_213]

Re: Tangent Amp - problem with display

This is my display. I thing this is perfect to replace. But i don't know where is the problem..., on backlight or some circuit https://www.aliexpress.com/item/1602...2-515552f21762

[R_J]

Re: Tangent Amp - problem with display

Did you check to see if there is any voltage to the backlight terminals in the display, thats the 2 leads going to the white piece. I don't know what the source of light is, I suspect it is one or two white led

I know the link I posted had a different problem, I posted the link because it had pictures of the display and showed the white backlight on the side.