Denon 1306 front VFD display not working

[srt1]

hi, I got recently Denon 1306, the problem was protection mode is active due to one channel transistors blown, So i replaced Transistors now everything fine,
Except front VFD display , it was working even in protection mode also, but now i dont know what happend suddenly. i checked ac suplly of VFD as per schematic also -VTT volts its all are within specified limit,. Anybody can help me on this

[stj]

Re: Denon 1306 front VFD display not working

cracked solder joints?

[srt1]

Re: Denon 1306 front VFD display not working

cracked solder joints?

I didnt see lose connection..i checked volatages at every pin of vfd its showing -34volts..

[sam_sam_sam]

Re: Denon 1306 front VFD display not working

Did you check the caps near the VFD display and in the power supply with an ESR meter I have ad it where when the caps are going bad it mess with the display

Or the display or the controller is going bad if you can not find a bad soldering joints
Look at the soldering joint with a magnifying glass very closely for cracking and if you see a lot of flux around a joint re heat or remove the solder from the joint and redo it

[Longbow]

Re: Denon 1306 front VFD display not working

VFD's are multiplexed displays. Your display apparently has the usual -35 volt anode voltage, so that's one requirement. Looking at the schematic you will see a number of pins of the display micro labled G1, 2 ,3..etc and these lines must be active in order to turn on various segments. On the extreme ends of the VFD, you will see pins marked "F" or filament. Filament voltage is usually around 3V and has its own isolated supply referenced to the -35v. So check the filament supply. Since the display worked before your repair, you might check the owner's manual for reset instructions. Also, some of these things have a "display off" feature in the menu..not impossible.

[srt1]

Re: Denon 1306 front VFD display not working

VFD's are multiplexed displays. Your display apparently has the usual -35 volt anode voltage, so that's one requirement. Looking at the schematic you will see a number of pins of the display micro labled G1, 2 ,3..etc and these lines must be active in order to turn on various segments. On the extreme ends of the VFD, you will see pins marked "F" or filament. Filament voltage is usually around 3V and has its own isolated supply referenced to the -35v. So check the filament supply. Since the display worked before your repair, you might check the owner's manual for reset instructions. Also, some of these things have a "display off" feature in the menu..not impossible.

Thank your for all of your support on this , yes i already checked filament supply voltage it coming directly from transformer that is AC voltage , its around 5 volt, i already tried reset , but no success , there is no display off ro dim button on front panel, as my knowledge even the display off inside the menu , when i am reseting i hope it will became normal condition , but something wrong happend anywhere while i am doing repair but its nothing get shorted. also i replace the ribbon cable which connecting the front panel display board to main board but no success

[srt1]

Re: Denon 1306 front VFD display not working

Did you check the caps near the VFD display and in the power supply with an ESR meter I have ad it where when the caps are going bad it mess with the display

Or the display or the controller is going bad if you can not find a bad soldering joints
Look at the soldering joint with a magnifying glass very closely for cracking and if you see a lot of flux around a joint re heat or remove the solder from the joint and redo it

i will try re soldering, i dont have ESR meter to check capacitors, but non of capacitors have bulge sign..

[srt1]

Re: Denon 1306 front VFD display not working

hi, i re solder ll connectors but no success also i replaced the controller ic i got same from another denon.but still no display , any suggestions

[Longbow]

Re: Denon 1306 front VFD display not working

Can you post a schematic of the display area? Thanks.

[srt1]

Re: Denon 1306 front VFD display not working

Can you post a schematic of the display area? Thanks.

Here is the schematic

[Longbow]

Re: Denon 1306 front VFD display not working

Sorry, that .pdf isn't working. I found a schematic, however. All I can say is follow the usual procedure. Important input to the display board is on connector CP301A, pins 9, 10, 11, 12. And of course the power on pins 19, 20, with ground on pins 17, 18. Note ZD301 which references the filaments to the -35 volts.

Make sure the chip is not being held in reset - pin 61 should be high. The tube is a triode. The filaments are -35v. The segments will light if the grid and anode are grounded (more positive than the filaments). The display chip multiplexes the grids and anodes. All the pins labeled "G" on the display chip will normally be active, (i.e. must be sending pulses.) The pulses must go from -35 volts to ground.

As you can see, each of the display pins are pulled down to -35v by the pull-down resistors connected to pin 20 of connector CP301.

Summary: The chip has to have -35v and +5v power. RST should be high. G and A pins should be active to light the segments. There must be clock, data, and chip enable on chip pins 62, 63, 64. Take a close look at Q310, Q311 which could hold off the display.

Good luck.

[srt1]

Re: Denon 1306 front VFD display not working

Sorry, that .pdf isn't working. I found a schematic, however. All I can say is follow the usual procedure. Important input to the display board is on connector CP301A, pins 9, 10, 11, 12. And of course the power on pins 19, 20, with ground on pins 17, 18. Note ZD301 which references the filaments to the -35 volts.

Make sure the chip is not being held in reset - pin 61 should be high. The tube is a triode. The filaments are -35v. The segments will light if the grid and anode are grounded (more positive than the filaments). The display chip multiplexes the grids and anodes. All the pins labeled "G" on the display chip will normally be active, (i.e. must be sending pulses.) The pulses must go from -35 volts to ground.

As you can see, each of the display pins are pulled down to -35v by the pull-down resistors connected to pin 20 of connector CP301.

Summary: The chip has to have -35v and +5v power. RST should be high. G and A pins should be active to light the segments. There must be clock, data, and chip enable on chip pins 62, 63, 64. Take a close look at Q310, Q311 which could hold off the display.

Good luck.

Thank you very much forall the informations ,let me start on this . and i will update you