All 4 would fill the bill just fine, if forced to choose I would go with the 105 degree 63v cap.
Pioneer SX-890 problems again...
- Thread starter tk3768
- Start date
But who says that's a bad thing as long as it fixes or improves something!
One other thing on the 4.7 ohms measurement. Short the two meter leads together (no connection to the circuit) to see what the meter reads. Then subtract that amount when measuring the actual part. You already have that number so don't un-solder the part again. It looks like you did a good job soldering the jumper in!
Got the parts!
Alright Mark, here goes:
Replaced all the power transistors, replaced the sa899's, the sc1904's and the sc1775's, and then the sc1913 and the sa913 for the left channel, the sa913 being the one that was shorted besides the sb705a. Checked the solder joints and they all look good. Anything else? I'm not powering it on until you say so.
Photo of the replaced power transistors. Just to confirm, does the order look right? (Photo turned upside down)
Thanks
Todd
Alright Mark, here goes:
Replaced all the power transistors, replaced the sa899's, the sc1904's and the sc1775's, and then the sc1913 and the sa913 for the left channel, the sa913 being the one that was shorted besides the sb705a. Checked the solder joints and they all look good. Anything else? I'm not powering it on until you say so.
Photo of the replaced power transistors. Just to confirm, does the order look right? (Photo turned upside down)
Thanks
Todd
The correct placement is one thing I cannot easily positively confirm right now.
You should have documented or photographed everything before disturbing it.
Also when powering up first the idle current pot HAS to be turned down to zero ohms on both sides, and the unit MUST be hooked up to the dim bulb tester.
If the transistors are reversed, the dim bulb will glow brightly continuously. Otherwise it will dim down after the caps charge after power up.
After that one channel at a time must be tested for no problems by setting the idle current THEN TURNING IT BACK DOWN TO ZERO.
Once no monsters jump out of hiding with the idle current settings test, the dim bulb tester can be disconnected and the idle currents set for real.
You should have documented or photographed everything before disturbing it.
Also when powering up first the idle current pot HAS to be turned down to zero ohms on both sides, and the unit MUST be hooked up to the dim bulb tester.
If the transistors are reversed, the dim bulb will glow brightly continuously. Otherwise it will dim down after the caps charge after power up.
After that one channel at a time must be tested for no problems by setting the idle current THEN TURNING IT BACK DOWN TO ZERO.
Once no monsters jump out of hiding with the idle current settings test, the dim bulb tester can be disconnected and the idle currents set for real.
Okay Mark, I have the dim bulb tester built, thanks to inkboy1's post: http://www.audiokarma.org/forums/showpost.php?p=2662863&postcount=1
I have the idle current pots turned all the way to the left, same with the dc balance pots. Is this correct? And what wattage of bulb do you recommend I start with? I have 15, 40, 60 and 100 watt bulbs.
Thanks
Todd
I have the idle current pots turned all the way to the left, same with the dc balance pots. Is this correct? And what wattage of bulb do you recommend I start with? I have 15, 40, 60 and 100 watt bulbs.
Thanks
Todd
Okay, we have a happy ending! I did a little research and found you want a lower bulb wattage to start with and the pots turned all the way left was correct, so I put the left channel jumper back in and replaced the main caps before I turned it on, then started with the 15 watt bulb.
Flip power switch, bulb goes bright as the main caps charge, and then faded quickly to a slight glow, relay clicks about 5 seconds later. Good.
The panel lights were a little dim, so I put in the 40 watt and powered it on again. Lights at normal level, relay clicks. Same with the 60 and 100 watt bulbs. I go ahead and set the dc balance and idle current one channel at a time, then turn it back down to zero. Nothing out of place, everything sets just fine.
Power off, unplug from the dim bulb tester and plug it in and turn it on. Same thing as above, I set the dc balance and idle current and hook it up to my CD player. We now have music!
Amazing sound, I thought it was good before but now...The high end is even clearer then before, the bass more powerful, all I can say is wow! It even brought out the imperfections in my CD player that I had not heard before, bad enough that I had to switch to a another one! And I'm using Sanyo SS-660 speakers, which are not exactly high quality!
A big thank you, thank you, thank you to Mark and Glen for all their guidance, and I couldn't have done this with out you, Mark
Glen, it would appear that it was a bad transistor that was affecting the bias.
However, one slight problem remains, and that is the THD has not changed. I also noticed that when ever I turn the treble knob from flat to a lower or higher setting, it emits a pop though the speakers, but only when you turn it from flat and it has been at flat for 4-5 minutes. If you turn it back and forth it's silent. Bad cap?
Below is her playing at low volume, photo is not the best, but the attachments have a size limit.
Thanks so much again for all you guys have done.
Todd
Flip power switch, bulb goes bright as the main caps charge, and then faded quickly to a slight glow, relay clicks about 5 seconds later. Good.
The panel lights were a little dim, so I put in the 40 watt and powered it on again. Lights at normal level, relay clicks. Same with the 60 and 100 watt bulbs. I go ahead and set the dc balance and idle current one channel at a time, then turn it back down to zero. Nothing out of place, everything sets just fine.
Power off, unplug from the dim bulb tester and plug it in and turn it on. Same thing as above, I set the dc balance and idle current and hook it up to my CD player. We now have music!
Amazing sound, I thought it was good before but now...The high end is even clearer then before, the bass more powerful, all I can say is wow! It even brought out the imperfections in my CD player that I had not heard before, bad enough that I had to switch to a another one! And I'm using Sanyo SS-660 speakers, which are not exactly high quality!
A big thank you, thank you, thank you to Mark and Glen for all their guidance, and I couldn't have done this with out you, Mark
Glen, it would appear that it was a bad transistor that was affecting the bias.
However, one slight problem remains, and that is the THD has not changed. I also noticed that when ever I turn the treble knob from flat to a lower or higher setting, it emits a pop though the speakers, but only when you turn it from flat and it has been at flat for 4-5 minutes. If you turn it back and forth it's silent. Bad cap?
Below is her playing at low volume, photo is not the best, but the attachments have a size limit.
Thanks so much again for all you guys have done.
Todd
