SimontY said:
We need to know the voltage either side of R854. Its possible Q852 is not switching, either by failure of no 5V switched from Q853 etc.
A 2V drop across D853 is not right as it should be 4.7V. Q851 looks like it may be high output due to no load.
Brent
rowemeister said:
28v out of reg😱
with or without load?
the regulator is not regulating
it should be -18v reference to its grd pin.
-28v on zener d853 is the zeners refer voltage?
allan
awpagan said:
Right ok, I wasn't sugesting this was right I just think the problem is elsewhere so I tried this...
I removed the diode D852 from Q851 on mine.
Now the reg has no gnd reference and the gnd pin is -32v and output -30V.
The display still works.
-----------------------------------------------------------------------------
This is your setup Simon
If I short D852 so gnd pin is gnd and output is -18V as expected.
R852 R853 should have 13.3V
D853 should have 13.5V on cathode
R854 should have 12.6V transistor side and 5v other side
Brent
SimontY said:Good evening 63 Crew!
Voltage at R854 is -26vdc BOTH sides
Evening Simon. Time to crack that stubborn display of yours 😀.
So Q853 is not conducting. Try shorting Q853 in several ways, you won't break anything doing that. Does the display light up? What's the voltage on RN06, R855 and RN09?
Ray.
RN06- 0v
R855- -2.4v
RN09- 0v
Any clues?? lol
Going to a local for a couple of ales, but I'll be back for more testing soon hopefully
Certainly tomorrow morning.
R855- -2.4v
RN09- 0v
Any clues?? lol
Going to a local for a couple of ales, but I'll be back for more testing soon hopefully
Certainly tomorrow morning.
SimontY said:RN06- 0v
R855- -2.4v
RN09- 0v
Any clues?? lol
Going to a local for a couple of ales, but I'll be back for more testing soon hopefully
Certainly tomorrow morning.
O.k. cheers! Have a nice drink!
Is that RN06 voltage across it, or on each side of RN06 0V? One side should be 0v, since it's connected to ground. R855 is not correct.
Ray.
ray
what is the current draw for the dac and the decoder?
just acquired a couple of audiocom regs😀
one for the clock
one for the dac and maybe the decoder
depends on current.
allan
ps the cd67 sounds better though the speakers than headphones
now i need to build a better headphone amp
what is the current draw for the dac and the decoder?
just acquired a couple of audiocom regs😀
one for the clock
one for the dac and maybe the decoder
depends on current.
allan
ps the cd67 sounds better though the speakers than headphones
now i need to build a better headphone amp
awpagan said:
Hi Allan,
The DAC needs 15...25mA for the digital supply (DVdd), 3...5mA for the 'analog' supply (AVdd) and 1 or 2 mA for the clock supply (XVdd), according to the datasheet.
The decoder needs a total of 49mA says the sheet.
Gee, more boring DIY'ing. We have a tough life!
Regards,
Ray.
6h5c said:O.k. cheers! Have a nice drink!
Is that RN06 voltage across it, or on each side of RN06 0V? One side should be 0v, since it's connected to ground. R855 is not correct.
Ray.
0v either side 🙁
SimontY said:
Hm, that could mean Q853 is broken, assuming all the PCB tracks are o.k. No voltage on the base is not possible. Do you have a universal PNP to replace it? Any small 2SA... or a BC55x will do, pinning is different though.
Ray.
The muting ones are all NPN, but you could rip out a 2SA970 (QH05...08) from the HDAM circuit 😀.
Ray.
Ray.
Cool 🙂 You think that transistor is the problem? Could it still be just a dry joint? I guess I need to check a few things for continuity.
If Q853 is shorted the display lights up, so all the nescessary voltages are present. But on RN06 is 0V, and that should be 4.4V, coming out of Q853. In theory it could be a bad joint, not connecting Q853 to RN06, but if you measure directly on Q853's most right pin and there's still 0V..... There's only a few mm. between the two 😀.
Ray.
Ray.