Kenwood KA-7300 Integrated Amplifier Issues
- Thread starter captainclock
- Start date
captainclock
Pacifist Otaku
I did do it properly and carefully when I worked on those VCRs, its just that they had put too much solder on the connections and also ontop of that they were pretty crappy made circuit boards because the "varnish" (the green stuff ontop of the circuit traces) started bubbling and boiling way before the solder started melting, so you can't blame that on user error! Blame that on poor craftsmanship!
sake
Active Member
The relay itself is the most expensive part coming in at $11.83.
From Digikey: Omron MY4-02-DC24 - Z2634-ND.
Including shipping, I can't see it costing >$30 to do what is discussed in the link I provided.
If you really want to just dump that amp and ever get near Chicago, let me know, I'd gladly take if off you hands.
sake
Active Member
captainclock
Pacifist Otaku
No thanks, the place where I work does electronics recycling and I'd rather support them, thank you very much, besides I don't wish to ever drive around Chicago, too many idiots on the road over there.
captainclock
Pacifist Otaku
And what's so hard to believe about my statement? You honestly think that any VCR made towards the end of the VHS era was going to have High Quality parts in it?! Maybe back in the hayday of VHS back in the 1970s and 1980s but not in the 1990s and 2000s, during the later period of VHS they tried to make them as cheaply as possible including skimping on the production of the parts in them, including on the circuitboards, so don't give me that crap!
sake
Active Member
You sir, are a special breed. Best of luck with all you do going forward, your gonna need it.
captainclock
Pacifist Otaku
You sir, are a special breed. Best of luck with all you do going forward, your gonna need it.
Sorry I don't believe in luck, and I don't think you even needed to say that, because its my amplifier I can do whatever I want with it, and if I decide that its not worth my time and energy to fix the thing after hearing and seeing what all its going to take to repair it then its my choice to decide what I want to do next with the unit and if I decide I want to recycle the unit then I'll do it, its a free country and nobody can tell me what I can and can't do with the stuff I have, I mainly posted this thread so I can find out what was causing the amplifier to do what it was doing and to find out how involved the repair work would be, and I found out what I needed to know and I made my decisions from there as to what I wished to do from there, I didn't post this thread just to get trolled on by people who think that they're better than me and think that they're doing the audio world a favor by ousting someone who they think is supposedly a threat to all things audiophile.
So if you don't have anything nice to say then don't say it at all!
captainclock
Pacifist Otaku
And also I got the back off and I'm trying to flip the relay board over and its not budging the wires aren't slack enough, I feel like I'm going to break wires and connecting posts off the board if I try to bend it any further, like I said its not possible to service the relay board in the manner that you guys are saying that it can be done because I don't have enough wire slack to allow the circuit board to bend over without risking breaking wire connections and or the board itself.
So like I said its just gonna have to go to the electronics recycling at my work.
So like I said its just gonna have to go to the electronics recycling at my work.
captainclock
Pacifist Otaku
And Seriously why is it so hard for you people to accept the fact that you might actually be wrong about something for once? I mean is it really that hard for you to believe that there might of been more than one version of the KA-7300 Amplifier out there? Who's so say that I might not have an older version of this amplifier which may of had a relay board that had to be unwired from the unit in order to service it and the one mentioned in the other thread linked to in here wasn't maybe a later revision of this unit that didn't require unwiring the circuitboard to service it?
Those kinds of things happened all the time in the electronics world, that's why when you looked at service manuals from different electronics back in the day you might of had as many as 4 or 5 different versions of the same model radio or amplifier but were chassis numbers, that's because they would often times do revisions of a radio or amplifier's chassis setup to improve upon the original because maybe the original had some design flaws that weren't necessarily good for the customer or the repairman so they would revise the original chassis to eliminate any previous design flaws that may have been present in the original.
Did you guys ever think about that being a possibility with this particular model?
Also what works for one problem doesn't necessarily work for another, just because I have the same model of amplifier as the other person in this forum had and was having the same issues, doesn't necessarily mean that the way he fixed his problem is going to fix my problem, because you have to take into account that no two amplifiers are going to be designed exactly the same way even if they're the same exact model, because again more than likely Kenwood made design changes to this model amplifier during its production run and I might of had an earlier production run model that used the initial design concept and then the one the other guy on here had might of been a later production run model that might of had some design changes since mine was made, which would mean that if your service manual you have was for a later production model unit then it would basically be useless for an early run model because of design differences, and hence why there isn't always a one size fits all solution to every problem.
Those kinds of things happened all the time in the electronics world, that's why when you looked at service manuals from different electronics back in the day you might of had as many as 4 or 5 different versions of the same model radio or amplifier but were chassis numbers, that's because they would often times do revisions of a radio or amplifier's chassis setup to improve upon the original because maybe the original had some design flaws that weren't necessarily good for the customer or the repairman so they would revise the original chassis to eliminate any previous design flaws that may have been present in the original.
Did you guys ever think about that being a possibility with this particular model?
Also what works for one problem doesn't necessarily work for another, just because I have the same model of amplifier as the other person in this forum had and was having the same issues, doesn't necessarily mean that the way he fixed his problem is going to fix my problem, because you have to take into account that no two amplifiers are going to be designed exactly the same way even if they're the same exact model, because again more than likely Kenwood made design changes to this model amplifier during its production run and I might of had an earlier production run model that used the initial design concept and then the one the other guy on here had might of been a later production run model that might of had some design changes since mine was made, which would mean that if your service manual you have was for a later production model unit then it would basically be useless for an early run model because of design differences, and hence why there isn't always a one size fits all solution to every problem.
Last edited:
That unit happens to be one of Kenwood's better integrated amps. How expensive to fix? If you were local, I'd do it for a six of Guinness, and share it with you while you sat here here watching me fix the amp over the 90 minute period that it took to do the work. Or I least I would have, until I caught wind of your needless shitty attitude.
Do yourself (and the vintage audio world) a favor and find another hobby. Just like the wiring to that board, I fear you are wound a little too tight for this.
Do yourself (and the vintage audio world) a favor and find another hobby. Just like the wiring to that board, I fear you are wound a little too tight for this.
I have never worked on a KA-7300, but from the pictures, and the position of the suspect transistor (post #10 thank you sake) I believe there is easily enough room to get to the board and change that transistor - even without removing/dropping the rear panel. It is a pity you do not feel capable of doing this, and are not apparently prepared to accept that it may be best done by an expert in this case.
Of course if you were to 'rebuild' the board in question it would be extremely advantageous to actually remove the board. This is the kind of stuff the real knowledgeable tech's here do almost every day, several have posted here to try and help you.
Of course if you were to 'rebuild' the board in question it would be extremely advantageous to actually remove the board. This is the kind of stuff the real knowledgeable tech's here do almost every day, several have posted here to try and help you.
Last edited:
In before the lock. The biggest problem with lifting traces on a printed circuit board, any board, is too much heat or heat for too long. A soldering iron used on Tube gear with point to point wiring may be too hot for a printed circuit board on SS gear. (that would be an example of one size fits all trying to use the same iron for two different types of work). Granted, not everyone has extra tools to work on different types of jobs. But using a possibly too hot iron on more delicate work requires a lot of patience, some heat sinking, and experience IF its going to work at all.
And you could also be right in that a lot of consumer gear just isn't made to be worked on easily or at all. But most of the vintage gear including the Kenny is straightforward to work on. Just because you don't seem to find a way to do it, perhaps being unfamiliar with that particular unit's arrangement and how to disassemble it, doesn't mean there isn't at least one or two ways to get it done.
Others who have experience with this unit and similar ones have given you suggestions. You are certainly able to send this to the recycler or trash can it, whatever you wish. I'm suggesting that patience, a break from the frustration of working on this, or doing a bit more research on the repair before going back to it, may yield a new result.
All of us have been in the same boat, hitting some unseen obstacle, till we get that "duh!" moment, and the result becomes clear, sometimes even obvious. Sometimes that comes from us on our own, most times it comes from someone else - a casual observer, an experienced pro, occasionally from the wife, boss, or co-worker. An open and relaxed mind may be the best remedy.
As for costs, if you don't want to recoup your costs by selling it, is the recycler going to give you some $$ for it?
And you could also be right in that a lot of consumer gear just isn't made to be worked on easily or at all. But most of the vintage gear including the Kenny is straightforward to work on. Just because you don't seem to find a way to do it, perhaps being unfamiliar with that particular unit's arrangement and how to disassemble it, doesn't mean there isn't at least one or two ways to get it done.
Others who have experience with this unit and similar ones have given you suggestions. You are certainly able to send this to the recycler or trash can it, whatever you wish. I'm suggesting that patience, a break from the frustration of working on this, or doing a bit more research on the repair before going back to it, may yield a new result.
All of us have been in the same boat, hitting some unseen obstacle, till we get that "duh!" moment, and the result becomes clear, sometimes even obvious. Sometimes that comes from us on our own, most times it comes from someone else - a casual observer, an experienced pro, occasionally from the wife, boss, or co-worker. An open and relaxed mind may be the best remedy.
As for costs, if you don't want to recoup your costs by selling it, is the recycler going to give you some $$ for it?
captainclock
Pacifist Otaku
Well I'm very sorry about last night it was very unacceptable what I did and I apologize, but I also was very frustrated that everyone on here thought that they had to insist that what I was saying about my relay board setup was wrong which is why I went off like I did.
Also as an update it seems that I had to take the large power supply capacitors loose (unscrew their mounting brackets from the chassis) in order to get the relay board to move any further so now it seems that my soldering iron has more room in there to work without fear of toasting the power supply caps. :yes:
Last edited:
captainclock
Pacifist Otaku
Last edited:
captainclock
Pacifist Otaku
Well in my case I'm just going to replace all of the capacitors and take the transistor out and test it in my transistor tester on my multimeter and then if the tranistor still tests good then I'll put it back in and fire it up after replacing the capacitors and if the relay kicks in like it should we'll know it was just bad capacitors onboard and it was nothing to worry about and that it was just a simple repair that we didn't need to fuss over. :thmbsp:
:yes:
Ok captainclock - that's fair enough. 
On the off-chance that it doesn't work after changing the capacitors, don't be afraid to change that transistor anyway - even if it tests good on the transistor tester - as sometimes they don't find the issue you are trying to pin down. (if you do, please check the pinouts on the suggested replacement transistor, it could be different to the original). :thmbsp:
On the off-chance that it doesn't work after changing the capacitors, don't be afraid to change that transistor anyway - even if it tests good on the transistor tester - as sometimes they don't find the issue you are trying to pin down.
(if you do, please check the pinouts on the suggested replacement transistor, it could be different to the original). :thmbsp:
Last edited:
captainclock
Pacifist Otaku
Ok captainclock - that's fair enough.
On the off-chance that it doesn't work after changing the capacitors, don't be afraid to change that transistor anyway - even if it tests good on the transistor tester - as sometimes they don't find the issue you are trying to pin down.
OK, thanks, so what would be a suitable replacement for a 2SD414 transistor? I tried googling it and all I came up with was a TO-126 something or other but when I looked it up nobody had it... :scratch2:
Scratch that it seems that Digikey has it but I have no idea if its the correct substitute or not because I looked at the link again that I found that info on and it seems that the link working again and the 2SD414 is just a part number not the actual transistor number...
Last edited:
2SD414? - I thought we were talking about the protection board transistor assessed to be a 2SC1213 whose available equivalent is a KSC2383YBU (from Mouser) ?
wait one - I'll look up the 2SD414.... EDIT UPDATE: = KSC2690 (again Mouser).
Is that what the relay driver transistor actually is - a 2SD414?
wait one - I'll look up the 2SD414.... EDIT UPDATE: = KSC2690 (again Mouser).
Is that what the relay driver transistor actually is - a 2SD414?
captainclock
Pacifist Otaku
I thought so too but another look at the relay board revealed that it had as the driver transistor a 2SD414 on it instead of a 2SC1213.
Isn't it strange how some subtle differences between models can make a huge difference in the repair?