Well, a good indication that all is ok is if you have close to 0 volts at the feedback connection point and can adjust the DC balance for 0 volts. Set the bias control about 1/4 of the way up at first as well to be sure there is some current flowing through the driver devices. You can easily drive a small speaker(sometimg like a Yamaha NS-10) to a decent level with just the driver board. If you get this far and all is well then wire in the outputs as well.
Also compare your easurements to mine thata re in the wiki.
Hope some of this helps...
Mark
Also compare your easurements to mine thata re in the wiki.
Hope some of this helps...
Mark
Mark,
I took measurements on the two boards I assembled and compared them to your posted results. That’s how I realized one of them was completely out of whack. I have now connected the one that measured close to yours to a small original factory speaker that I had removed from my car, and played it for almost an hour. It seems to be working fine with no audible distortion. The problem with the other one is still a mystery that persists after replacing all transistors, but I am determined to find it.
Thank you for the info on driving the speaker without the output devices.
I took measurements on the two boards I assembled and compared them to your posted results. That’s how I realized one of them was completely out of whack. I have now connected the one that measured close to yours to a small original factory speaker that I had removed from my car, and played it for almost an hour. It seems to be working fine with no audible distortion. The problem with the other one is still a mystery that persists after replacing all transistors, but I am determined to find it.
Thank you for the info on driving the speaker without the output devices.
Grimberg,
Measure all the resistors to be sure that one is not in the wrong place... be sure to lift one end of each one!! Its easy to do.... I did it on one of mine. Especially if all the transistors have been replaced..... This is most likely your culprit... I measure mine going onto any boards I assemble now since my eye sight is not what it was when I was 19.
Mark
Measure all the resistors to be sure that one is not in the wrong place... be sure to lift one end of each one!! Its easy to do.... I did it on one of mine. Especially if all the transistors have been replaced..... This is most likely your culprit... I measure mine going onto any boards I assemble now since my eye sight is not what it was when I was 19.
Mark
Inspired by Grimberg, I picked up the screwdriver a while ago and started go work on my clone as well. Since I have dual mono I plan to check one channel at a time beginning with the one that I mounted the Daleresistors with the typing up on, that way I don't need to desolder them to make sure that they are at the right place. So the plan is to put everything in the right place and connect the main and driverboard of the first channel tonight, tomorrow afternoon I'll fire it up again and take some measurements to see if and which transistors are blown. I'll post the values here for confirmation and then replace the faulty components. Hopefully I'll have one channel working soon and with that I can move on to the next channel.
So please look in from time to time
So please look in from time to time
The shoppingtour took a bit more time than expected so I only managed to get the stuff wired. Everything up to the driverboards.
And today it seems like the boss forgot to use his glasses for when arriving at work, expecting a slow 4-5h of overtime there was twice the amount of work waiting for me but with some luck I'll be able to get home in time to take some measurements.
When taking the measurements I should have the inputs shorted and the three connections between driverboard and output disconnected. Nothing else to take into account?
And today it seems like the boss forgot to use his glasses for when arriving at work, expecting a slow 4-5h of overtime there was twice the amount of work waiting for me but with some luck I'll be able to get home in time to take some measurements.
When taking the measurements I should have the inputs shorted and the three connections between driverboard and output disconnected. Nothing else to take into account?
So, finally I have gotten the time to take the measurements but somethings fishy, could you guys take a look? All values in volts unless otherwise specified.
MPSA42= 101 103 106
MPSA92= 102 104 105
MJE15032= 108 109 111
MJE15033= 107 110
Q E B C
Q-101 35,6 1,2mV -0,624
Q-102 -35,3 -2,5mV 0,627
Q-103 35,3 1,6mV -0,600
Q-104 -35,3 1,6mV 0,539
Q-105 0 35,4 36,0
Q-106 0 -35,4 -36
Q-107 36,6 36,1 1,635
Q-108 -36,5 -35,8 -1,404
Q-109 1,027 37,6 1,634
Q-110 -0,792 -37,6 -1,402
Q-111 -1,402 1,633 -0,815
Railvoltages are 37,6 VDC (+&-) but if measuring AC between positive rail and ground I get 82,9VAC. Nothing between negative and ground. Further more I seem to get the values of the MPSAs thrown about but I have used the datasheet and it says it is correct.
And one more thing, why doesn't Grimberg have a Q110?
MPSA42= 101 103 106
MPSA92= 102 104 105
MJE15032= 108 109 111
MJE15033= 107 110
Q E B C
Q-101 35,6 1,2mV -0,624
Q-102 -35,3 -2,5mV 0,627
Q-103 35,3 1,6mV -0,600
Q-104 -35,3 1,6mV 0,539
Q-105 0 35,4 36,0
Q-106 0 -35,4 -36
Q-107 36,6 36,1 1,635
Q-108 -36,5 -35,8 -1,404
Q-109 1,027 37,6 1,634
Q-110 -0,792 -37,6 -1,402
Q-111 -1,402 1,633 -0,815
Railvoltages are 37,6 VDC (+&-) but if measuring AC between positive rail and ground I get 82,9VAC. Nothing between negative and ground. Further more I seem to get the values of the MPSAs thrown about but I have used the datasheet and it says it is correct.
And one more thing, why doesn't Grimberg have a Q110?
Crap, I missread the pinout just as last time.
This is how it should be:
Q C B E
Q-101 35,6 1,2mV -0,624
Q-102 -35,3 -2,5mV 0,627
Q-103 35,3 1,6mV -0,600
Q-104 -35,3 1,6mV 0,539
Q-105 0 35,4 36,0
Q-106 0 -35,4 -36
Q-107 36,6 36,1 1,635
Q-108 -36,5 -35,8 -1,404
Q-109 1,027 37,6 1,634
Q-110 -0,792 -37,6 -1,402
Q-111 -1,402 1,633 -0,815
This is how it should be:
Q C B E
Q-101 35,6 1,2mV -0,624
Q-102 -35,3 -2,5mV 0,627
Q-103 35,3 1,6mV -0,600
Q-104 -35,3 1,6mV 0,539
Q-105 0 35,4 36,0
Q-106 0 -35,4 -36
Q-107 36,6 36,1 1,635
Q-108 -36,5 -35,8 -1,404
Q-109 1,027 37,6 1,634
Q-110 -0,792 -37,6 -1,402
Q-111 -1,402 1,633 -0,815
I was just about to fix that but thanks
However, does anything seem to be wrong?
Q C B E
Q-101 35,6 1,2mV -0,624
Q-102 -35,3 -2,5mV 0,627
Q-103 35,3 1,6mV -0,600
Q-104 -35,3 1,6mV 0,539
Q-105 0 35,4 36,0
Q-106 0 -35,4 -36
Q E B C
Q-107 36,6 36,1 1,635
Q-108 -36,5 -35,8 -1,404
Q E C B
Q-109 1,027 37,6 1,634
Q-110 -0,792 -37,6 -1,402
Q-111 -1,402 1,633 -0,815
Ok, thanks.
If I where to connect a speaker to the driverboard, do I then use the feedbackconnection as a positive and leave the D+ and D- floating? Since I have a powerresistor of 6,8ohms I could easy use it as a dummyload and measure it for possible DC on the output before using real speakers.
If I where to connect a speaker to the driverboard, do I then use the feedbackconnection as a positive and leave the D+ and D- floating? Since I have a powerresistor of 6,8ohms I could easy use it as a dummyload and measure it for possible DC on the output before using real speakers.
Ok, Then I can do some minor tests before I try to get the hang of the oscilloscope. What I want to see if something bad happens at startup and shutdown, like a DC-surge or something nasty like that.
I looked at LGreens diagram over the temperature vs time at post 4375 and since the outputdevices stay just over 60degrees I was wondering at which temperature I should start to worry and how high it's "safe" . 65, 70 degrees? We're talking about MJ15003/4 TO-3 here