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| Re: Hustler transistor help Q8 - Q9 ??? [message #18912 is a reply to message #18911] |
Thu, 27 June 2013 07:20   |
stevem
Messages: 4775
Registered: June 2004
Location: NY
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Senior Member |
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Hello.
Q8 and Q9 are the the two main output transistors.The orignal ones where made by RCA and are number 36892 and these where matched for Kustoms use by RCA which is a important feature that I will get to.
There are many replacements for them these days, such as NTE electronics brand NTE131, or the NTE upgrade NTE181,or the generic type made by many 2N3055 which can even be found at radio shack, or at parts express.
The issue that I made mention of before is that they should be matched for the best amount of clean auido wattage, low 120 hz idle hum and even heat output as the amp is cranked.
You can use un-matched ones and the amp will not be harmed, but it may not perform to its full ability.
Also note that these transistors are mounted on a clear mica insulator that is coated on both sides with transistor heat sink compound. most times new transistors come with new mica insulators, but you will need a small tube of the heat compound.
When appling the compound you only need a very light film of it, just enough to fill in the very very small metal voide`s on both the transistor side and the amps heat sink/mounting bar.
Excess compound that is enough to get on the two connection pins can make for a bad connection, and repaired amps have failed due to this, so go light!
SK and GE, and Motorola are some other brands/manufactures of this common transistor.
The NTE181, and a Motorola number that I forget off the top of my head are transistors with a higher FE spec and as such will produce a bit more wattage than the others.
One good tip I can pass along is to use a fine tip marker to note on the heatsink which way the two wire slip on connector faces so you do not get it wrong.
Good luck with your repair and let us know how you make out.
[Updated on: Thu, 27 June 2013 07:34] Report message to a moderator |
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| Re: Hustler transistor help Q8 - Q9 ??? [message #18913 is a reply to message #18912] |
Thu, 27 June 2013 11:07 |
dallek1
Messages: 10
Registered: May 2013
Location: new york
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Junior Member |
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i think i has 2sd1175 in there does that sound right? also i had listed from this site nte130. i installed a matched set of nte130 , i measured 70 watts output on the bench ? the nte131 is a pnp ? thanks please check this?
a funny story, just a month or 2 back a local repair shop closed and dumped bags of semi useful stuff, i was there loading up my car, it just so happened there were a bunch os 130's , mostly egc but one matched set of nte130 ? i entered it into inventory and did not even realize i had them. cute
[Updated on: Thu, 27 June 2013 11:29] Report message to a moderator |
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| Re: Hustler transistor help Q8 - Q9 ??? [message #18914 is a reply to message #18911] |
Thu, 27 June 2013 12:08 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Yes the NTE131 are PNP and they are Germanium as well. He meant NTE130.
I'd guess that the 2SD1175s are just the power transistors that the previous tech had on hand to install when the amp was last repaired.
While convenient, NTE parts are priced way too high for me to use.
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| Re: Hustler transistor help Q8 - Q9 ??? [message #18918 is a reply to message #18911] |
Thu, 27 June 2013 17:17 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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The original chip was a uA739 which was the earlier version of the 4739. I use the XR4739 chips as replacements.
At times I have also installed 8 pin sockets and rewired the boards for more common 4558 chips as well.
Yes, they can be bright amps. I usually find that the 4-10 speaker setup works really well in a band situation where you can cut through the midrange and blend in the mix better.
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| Re: Hustler transistor help Q8 - Q9 ??? [message #18922 is a reply to message #18911] |
Fri, 28 June 2013 00:03 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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The original chip needed to have compensation caps added to it, which I believe were not needed on the 4739. I don't know if the newer chips would change the high frequency response of the amp
I'll have to look up the schematic for the other boards, but I believe that there is a 4558 dual op amp in the reverb section and there is one or two LM3080 transconductance amps in the trem/vibrato section.
One thing that I have found in the power amps of the older K200 amps, if you use modern transistors to replace the original drivers and outputs some of the power amps will start to oscillate in the ultrasonic frequency range due to the higher frequency response of the modern transistors.
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| Re: Hustler transistor help Q8 - Q9 ??? [message #18926 is a reply to message #18911] |
Fri, 28 June 2013 15:06 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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On the FX board PC5068 there are 3-LM3080 chips and 3-5558 dual op amps. Two of the 3080s are in the vibrato section and one is in the tremolo.
Two of the 5558 chips are part of the signal path/reverb and one is used as the low frequency generator for the vib/trem.
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| Re: Hustler transistor help Q8 - Q9 ??? [message #18931 is a reply to message #18922] |
Sat, 29 June 2013 13:52 |
dallek1
Messages: 10
Registered: May 2013
Location: new york
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Junior Member |
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hi this has me worried , the sl14228 according to what i read was replaced my several chips, i did not find any info on compensation caps? can you please point out which caps? are they on the signal (C13-C14 / C21-C22) or on the power (C15, C20)? please this would be very helpful. i find no datasheet on the sl14228, but the rc4739 does not even use legs 2,3,4 - 10.11.12 ? these are for caps (C13-C14 / C21-C22). so i can ignore these caps right?
[Updated on: Sat, 29 June 2013 14:09] Report message to a moderator |
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| Re: Hustler transistor help Q8 - Q9 ??? [message #18933 is a reply to message #18911] |
Sat, 29 June 2013 20:12 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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No need to worry.
I don't remember which caps and I don't have the schematic handy, but they are the small ceramic caps that are right next to the chip.
The original sl14228 was a house numbered uA739 chip. Try searching 739 chip, you should find a data sheet.
Yes, I think I mentioned that the 4739 chips do not need external compensation caps, so you can ignore them if you've used the new chip.
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| Re: Hustler transistor help Q8 - Q9 ??? [message #18940 is a reply to message #18911] |
Tue, 02 July 2013 06:24 |
stevem
Messages: 4775
Registered: June 2004
Location: NY
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Senior Member |
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I forgot to mention one important mod/improvment to make on the 5033 board while you are there.
The mod is to replace the two 5 watt emitter resistors with new ones that you stand up above the height of the two driver transistor heat sinks by passing the leads thru some 1/8" ID brass or aluminum tubing.
These two resistors dump alot of un-needed heat into both of those drivers!
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