Yes.
LF Lead Free
Leads either 100% tin plated (LF)
or
90% tin / 10% lead plated (blank, standard)
The LF was actually a bit less expensive,which is why it persisted in the lists, also stocked at higher levels.
LF Lead Free
Leads either 100% tin plated (LF)
or
90% tin / 10% lead plated (blank, standard)
The LF was actually a bit less expensive,which is why it persisted in the lists, also stocked at higher levels.
slayer44
Well-Known Member
Okay, so new relay is installed. Made a bracket inatead of standoffs like the others. Powering on with DBT only makes relay buzz so decided to hold my breath and plug it in directly. I have plenty of fuses. Powered on and relay clicks. No other sound at all!...I dont have the amps in at this point due to needing complete restoration. I am getting a consistant 73.7/-73.7 VDC on both channels. Schematic calls out 70/-70. Is a few volts over okay?
slayer44
Well-Known Member
Another quick question for when I get ready to power this on with amps connected...how do I prevent shorting when my trusty DBT doesnt seem to be working with this monster amp?...Larger wattage bulb?...using a 100 now. I do have a variac, should I use it?...I planned on installing one amp at a time and checking the voltages before installing the next. Just want to be sure because these outputs cost me 80 bucks.
One thing you can do is a number of ohmmeter measurements before you apply power. You can check the outputs metal cans to chassis ground. You can check the output triples from the bases of the pre drivers to the output summing or feedback point noting polarity of course.
You should turn the bias to minimum before applying power
Increase the lamp to 150w
The DBT is a very quick go no go test once the lamp dims as the ecaps charge up the test is over and you go to direct AC.
Your supply voltages are correct
I never use a variac
You should turn the bias to minimum before applying power
Increase the lamp to 150w
The DBT is a very quick go no go test once the lamp dims as the ecaps charge up the test is over and you go to direct AC.
Your supply voltages are correct
I never use a variac
slayer44
Well-Known Member
Awesome. Thanks rcs16. I always check for shorts on the cans/chassis as a precaution. Done these before. Now to find a 150 w incandescent!...stores are all LED now. Not entirely clear about the checking output triples part. Is this an ohm check between drivers and outputs?
slayer44
Well-Known Member
Got my stabistor repaired this morning. Intricate work with jewelers files, but managed to get about a 1/16th of wire exposed. Dollup of solder made a strong connection. Setting up with loctite adhesive now. It should work and I got resistance after all finished. Thanks Mark. I never thought about this method before. I will have to install the thing upside down though. Comes really close to the chassis cover.
Attachments
150w brooder lamp at a farm or restaurant supply but a 100w should work that’s all I use since it is quick test and is not meant for prolonged use
A output triple is the three Si junctions wired from bases to through emitters, as followers, through a few series resistors to the output starting from the VAS to the pre-driver. Your bias is for 6 Si junctions as part of the push-pull class AB output stage
A output triple is the three Si junctions wired from bases to through emitters, as followers, through a few series resistors to the output starting from the VAS to the pre-driver. Your bias is for 6 Si junctions as part of the push-pull class AB output stage
slayer44
Well-Known Member
I have another quick question in regard to the transistor bom's I see throughout AK. In the case of the 2SC945A's located everywhere, I see 512-KSC945CYTA and 512-KSC2383YTA being used. Is there a reason different transistors are being used?...or can I use all of one kind?...I have plenty of both.
The 945 is what was originally used. And what persists.
It's presence as a 945 is a pretty good indicator that the list wasn't generated by me(mtf).
THAT circuit POSITION discharges a 100uF cap (time on delay) to turn off the relay current.
That's a lot of energy, and so much gets soaked up in the transistor's active material so quickly, it is a danger to the transistor's survival.
Heat death from a powerful fast pulse.
So pioneer added a 22 ohm resistor in series with the discharge circuit to soak up some of the energy. They just took longer to die.
Instead I substituted a transistor that generates less heat to absorb ( Lower Vcesat) AND can handle much more current -
that results in a physically larger active material transistor that takes more energy to heat up that far.
Called "safe operating area" and is expressed as a graph in the data sheet.
There's also something else I dislike about the c945:
512-KSC945CYTA
512-KSC945YTA
easy to confuse them, huh?
the kicker:
512-KSC945CYTA is ECB
512-KSC945YTA is EBC
that cost me so much time troubleshooting over the years it became my standard FIRST question: "Did you use any a733 or c945 transistors"
still does.....
It's presence as a 945 is a pretty good indicator that the list wasn't generated by me(mtf).
THAT circuit POSITION discharges a 100uF cap (time on delay) to turn off the relay current.
That's a lot of energy, and so much gets soaked up in the transistor's active material so quickly, it is a danger to the transistor's survival.
Heat death from a powerful fast pulse.
So pioneer added a 22 ohm resistor in series with the discharge circuit to soak up some of the energy. They just took longer to die.
Instead I substituted a transistor that generates less heat to absorb ( Lower Vcesat) AND can handle much more current -
that results in a physically larger active material transistor that takes more energy to heat up that far.
Called "safe operating area" and is expressed as a graph in the data sheet.
There's also something else I dislike about the c945:
512-KSC945CYTA
512-KSC945YTA
easy to confuse them, huh?
the kicker:
512-KSC945CYTA is ECB
512-KSC945YTA is EBC
that cost me so much time troubleshooting over the years it became my standard FIRST question: "Did you use any a733 or c945 transistors"
still does.....
slayer44
Well-Known Member
Okay. Update here. Got my specially ordered 150 watt bulb and powered on. Got nothing. No soft start or, of course, amp relays. Followed the parts list religiously and VR set to zero ohms. Didnt touch the power limiter VRs at all. Every component on amp boards replaced except checked resistors. Whats next?...meter board? I was told this amp worked and only the outputs were stolen for another. DONT BELIEVE ALL EBAY SELLERS!...I read on here elsewhere to bypass the soft start when DBT checking. Dont know about that. Already got 150 bucks in parts here. Any suggestions?...I did buy all the new parts for the meter amp, so if thats my next step, so be it. By the way, the new amp relays are so tall they touch the inner chassis now. Didnt put any pressure on the amp boards, just touching. Also, I only have one amp in there for now. Maybe I need both for the protect circuit to act right?...anyway, any and all help is appreciated.
QSilver
Super Member
Not sure if this has been covered, but those relays are responsible for turning on the the right channel transformer milliseconds after the left channel. This reduces the inrush. They're are two in that picture as its the multi-voltage export model - they used two 120V relays in series to let it run on 240V. This is documented in the service manual.
slayer44
Well-Known Member
Qsilver. I have seen pictures of both. I am using only side of the relay as my schematic shows. I am fairly certain I followed the schematic. And I was getting 73.7 volts from both rails without any amps in. I bought 2 of these relays just in case. So if I should use 2, then I can go back and redo it...but its funny that I dont get any amp board relay movement, so I consider the meter board to be faulty.