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Kenwood KA-7300 Integrated Amplifier Issues

I'm not saying this IS the issue but it could be. I don't want to be held responsible if it doesn't fix the issue, it's merely a suggestion based on what you are describing.
 
bktheking said:
Correct , 4 transistors in total, 2 per board. I hope you have a meter that will do hfe, gain measuring cause you'll need to match each pair. If you don't know what this is Google it. Buy 10 transistors if you don't have them or if you have them then match 2 pair.
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I do have a multimeter that measures hFE for Transistors but I don't know if it works because I actually tried it earlier and I didn't get anything out of it number wise. Also the boards are marked on the top but not on the bottom so it makes it tricky trying to locate the transistors from underneath so don't accidentally unsolder the wrong components.

Also what's funny is that this issue was very similar to an issue I had with a couple of all in one units I had when I was younger one of them was a Soundesign unit and the other one was a Realistic Clarinette Series unit.
 
bktheking said:
Use a small flashlight to illuminate the board where the components are, you'll see it on the back side.
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I did use a small flashlight to light up the board but it's not going to be very helpful when I'm trying to hold a soldering iron in one hand and a supporting the amplifier in the other while trying to pull the old transistors out.
I actually do have some transistors that were from a multi-pack of Transistors that I had gotten from Radio Shack a while back but I don't think they are the correct ones to use with the application that I need them for.
 
2n what? You just need to locate the pins, nobody said anything about holding a flashlight and a soldering iron at the same time.
 
bktheking said:
They may , I'm not home to check the spec sheets.
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well if it helps any I have 6 of the 2N4403s and 3 each of the 2N2907s and the 2N3906s. I could look up the spec sheets for these transistors if you can tell me what I need to look for to see if they can be used or not.

Also I used some deoxit on the seperate/normal switch for the preamp on the back of the amplifier and it didn't seem to clear it up any.
 
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bktheking said:
And once I'm done should I send you a paypal invoice? :)
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Why? I'm the one doing all the work I even said I would look up the spec sheets for the transistors I have if you told me what to look for as far as what I needed to spot on the spec sheets as far as whether or not the transistors I have would make good subs for the originals.
 
bktheking said:
It was a joke , remember , loose.
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OK, well that was a pretty bad joke, now here's a really good joke for you by the way:

Did you know that drinking too much tea can be bad for you?
If you didn't then this will certainly make you think twice about drinking that 4th cup of Earl Grey.
There was once a Native American man that drank a whole gallon of tea one day and then he went to bed that night and drowned in his "teapee". :lmao:
 
It wasn't a bad joke, cause the way I see it your the one asking all the questions. I'm willing to help but the doing all the work part goes towards the physical repair, the knowledge part is the other half. So at this point I'll settle for 50%. I'll be looking up datasheets shortly.
 
bktheking said:
It wasn't a bad joke, cause the way I see it your the one asking all the questions. I'm willing to help but the doing all the work part goes towards the physical repair, the knowledge part is the other half. So at this point I'll settle for 50%. I'll be looking up datasheets shortly.
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Well I'm asking questions because I've not had to do this kind of extensive work with solid state stuff before.
The most I've ever done with solid state equipment was replacing capacitors or fuses, parts that didn't need reference sheets and cross-reference sheets and then substitution guides ontop of that, I've never had to replace Transistors before on anything solid state that I've worked on which Transistors are a lot harder to replace than say a capacitor or a reistor or a fuse because Transistors are more specialized and because of that if you don't find the right replacement part then you're SOL. Its not that I don't know how to do the work its just that I'm not familiar enough with the different types of transistors and what not to be able to know what I need to get or not get and how to replace them.
 
Unfortunately the circuit is looking for 48.5v on the collector and the ones you have are rated at 40v plus the gain is too low. the ksa992's are rated at 120v and the FB gain is what you need. KSA992FBU is what you should order.
 
bktheking said:
Unfortunately the circuit is looking for 48.5v on the collector and the ones you have are rated at 40v plus the gain is too low. the ksa992's are rated at 120v and the FB gain is what you need. KSA992FBU is what you should order.
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Well I ordered 25 of them from mouser, although thankfully they took paypal because otherwise I would of been stuck because I don't have a debit card anymore.
 
bktheking said:
Good luck with it.
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thanks, I just need to know how it is I use the hFE function on my multimeter to test the transistors to match them, because I've never used that feature before and I really don't know what I'm looking for as far as what needs to match and what the readout is supposed to look like.
 
Switch the meter to HFE, stick the transistor in the correct socket- PNP or NPN and pinout, usually ECB looking at the flat side left to right- check the data sheet if unsure and it should give you a reading.
 
bktheking said:
Switch the meter to HFE, stick the transistor in the correct socket- PNP or NPN and pinout, usually ECB looking at the flat side left to right- check the data sheet if unsure and it should give you a reading.
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OK, well could I practice and experiment with some of those transistors I already have laying around just to make sure it works correctly?
 
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