Anyone well versed in these? I added another to my collection and when I hooked it up to test, it worked for about 5 minutes and then just shut off. So I started looking for bad solder joints (which I should have done to begin with) and of course the remote turn on lugs were bad, fixed that, but it still won't come on. I have no "SWD ACC" from pin 8 of the upc494, so I go backwards.. (amp is completely unhooked btw) and I'm touching up solder joints for good measure...I touch pin 4 of the TAB194Z chip and the relay clicked...so becuase i'm "not much to lose here" I hooked it up, nothing....so i touch the soldering iron to pin 4 again...and it comes on and plays... so would the 2 turn on lugs being bad have caused the TAB194Z to fail? Or what might I be missing?
Anyone have a thought (other than I'm an idiot...)
Anyone have a thought (other than I'm an idiot...)
Are the various voltages present on the 8194 IC?
If you're touching your soldering iron to the circuit when voltage is on it, it could damage various components since it appears that the tip of your soldering iron is grounded.
If you're touching your soldering iron to the circuit when voltage is on it, it could damage various components since it appears that the tip of your soldering iron is grounded.
wow, thank you Perry. yes, it's grounded. (metcal soldering iron). I was just surprised that the relay engaged with no power or ground hooked to the amp. yes, the 8194 has the voltages in the manual present, it just appears to be dead. I haven't looked yet, but I assume given it's age, that IC may be hard to find.
Are you saying that the amp, with all required power, ground and remote, the voltages are as shown in the diagram?
Pin 4 is at 0v?
Pin 4 is at 0v?
ok, I went home for lunch and measured each pin. they are as follows. (with power, ground and both remotes powered.)
pin 1. 0.0v
pin2. 0.0
pin3 0.0
pin4 13.9
pin5 .011
pin6. 0.0
pin7.017
pin8 0.0
pin9 0.0
pin10 13.9
pin11 0.0
pin12 13.9
pin13 .033
pin14 13.9
pin 15 0.0
pin16 .001
pin 4 being at vcc can't be a good sign
pin 1. 0.0v
pin2. 0.0
pin3 0.0
pin4 13.9
pin5 .011
pin6. 0.0
pin7.017
pin8 0.0
pin9 0.0
pin10 13.9
pin11 0.0
pin12 13.9
pin13 .033
pin14 13.9
pin 15 0.0
pin16 .001
pin 4 being at vcc can't be a good sign
OK, I changed the cap on pin 5, it still shows .005. But pin 7 now shows 6.83v. The zener checked .6 one way and .7 the other
Do you have a 100k resistor (or anything relatively high) that you can connect between pins 5 and 7?
If so, try it to see if pin 5 comes up.
If so, try it to see if pin 5 comes up.
Assuming that the cap you installed isn't shorted, the IC appears to be shorted to ground, internally.
Well crud. I'll see about sourcing a new one. I found them on ebay for 10$ today. Thank you Perry
I'd ground pin 4 and run the amp a while to see if it has other problems. The protection will be disabled so be careful.
What happens to pin 5 (disconnect external resistor) and pull up pin 11 to the 12v supply with the 1k resistor?