Need to resurrect my HK Citation 22...

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Hello All:
My first post to this forum...glad to be in such capable company!!
I've owned a matched set of Harmon Kardon Citation 21 (preamp), 22 (200W/ch amp)
23 (FM tuner) since 1987, and for the most part, they have performed reliably and sound decent enough powering my homebrew speaker cabinets w/Seas drivers.

Unfortunately, the Citation 22 amp gave up the ghost whilst my family was celebrating Independence Day this year...the amp ran hot most of that day, and eventually the mini breaker on my surge strip tripped. A reset brought power back to the amp, but it never went fully back to its "green LED" operational mode.

Pulling the cover, it was apparent that one of its 250V/5A fuses had blown. After replacing the fuse and powering the amp on, one of its two power transformers hummed loudly for about one second, and the same fuse I just replaced blew again. Sounds like a blown transformer, correct?

I don't have the equipment to troubleshoot this any better than what I've described, but given the fact that it appeared to be the source of the hum, and it was noticeably warmer than the other transformer (even after just one second of power applied), makes me conclude there's a short in that transformer.

I was wondering if any of you concur that it <is> most likely a bad transformer, or if there are other components that need to be ruled out before I begin a hunt for a replacement transformer....which, by the way, is marked as follows:

Any suggestions, help, tips, or leads on where to pick up a replacement trans, would be most appreciated!!!
Thanks to all,
Jim Koeppel
Toms River, New Jersey, USA
Joined 2004
Paid Member
Hi Jim,
It sounds like you may have blown one channel (outputs + ? shorted). This is repairable. Do not reinstal another fuse or you may damage the power transformer. I would recommend you take this to a good shopo in your area. One that serviced HK under warranty would be preferred.

Output transistor(s)

I'am almost shure that your HK will be OK after replacing its output transistors.
In order to check if this components are the real cause of your fault, you might check with a tester (very useful and unexpensive instrument) if they are short. (it means that a huge amount of current flow throug them, causing the overheating and the humming of the transformer :hot:).
I hope it could help you.
Sorry for my bad english!:D
Joined 2004
Paid Member
Hi Jim,
How much experience do you have with amplifiers (repairing)? If not a lot then send it in. It's the small stuff that will get you. I know several shops that can't do this right and they get paid to do this!

Anyhow, normally it's not just the outputs that go. It's very important not only what you put in, but how you install the repalcement parts.

No offense to macchiajr, but I have no idea how "he" can be so sure of the outcome with no addition info. Proceed with caution least you create an unrepairable amplifier.

Joined 2004
Paid Member
Hi Giaime,
I had no doubt that they were. You should build a newer Marantz and compare them.

My main concern is that your Marantz was fairly tame, and you have a decent idea as to what comes next. A higher powered amplifier doesn't sit and smoke.... they go BANG !:hot: No warning. So depending on what experience Jim has determines what he should do next. It would be cool if Jim can fix his own unit.

So when you gonna build something Giaime?

anatech said:
So when you gonna build something Giaime?


Hi Chris! I just ended high school, and that one-tube radio that I built as a school project made me reach the highest peaks of school levels: 100/100 on the exams. :whazzat:
Photos here:
And me:

Next project? I will enjoy the summer :D and maybe build some kind of tube amp kit like this

(sorry for the OT people, but Chris is Chris ;) )
Troubleshooting Results....finally!!!

Well, after nearly five months, I found some time to troubleshoot this amp with a friend who is a very good electronics technician.
After some preliminary checks of the two power transformers on this dual mono amp, they both checked out OK. The individual power transistors on the right (defective) channel also appear OK, but there is a power rectifier (four pin, P/N D5Sb 40 73 ) that appears to be shorted across all four of its pins.
The left channel's rectifier appears to have acceptable resistance readings across its four pins. My next logical step is to replace the defective rectifier....but I cannot seem to find this part anywhere.
I have Googled the part number in every combination, checked electronics catalogs, but just can't seem to find any vendor that carries this part at all.
Any suggestions on how to purchase this item would surely be appreciated!!!!
I have attached a jpg photo file of the rectifier, if that will help...
Thanks for any assistance, suggestions, etc!!
Jim K.


  • rectifier.jpg
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Hello Jim!

I'm glad you succedeed in identifying the problem.

Please note that a shorted rectifier always takes with him many components, especially transistors. Carefully check every transistor on the board, not limiting to power ones.

The proper replacement for that part can be difficult to find: but any standard rectifier bridge should work.

Try at RadioShack or Digikey!
Joined 2004
Paid Member
Hi Jim,
You can replace that with a standard bridge rectifier with a hole in the center of the square, they also sell the original type. Have a look at the On Semi and IR catalogs.

Hi Giaime,
Power rectifiers are noramally blown by something else (high current flow), the filter caps will draw enormous current if presented with AC, but in the case the rectifier is shorted. So, what is your next project?

Same exact thing happened to mine

Back in 2000 I had this same amp overseas in Cairo Egypt running my pioneer cs-905's. Roof garden party strangely enough it was 4th of july party. All the americans would get together and celibrate. The amp ran fine all day and then like the sound of a pack of fire crachers every resister on both chans blew. With smoke rolling out of the top of the amp. I still have it and I check it seems my recs are still ok. Send me an email and I can desolder them and send them to you. If you pay shipping ill send the entire amp. I was going to send it in when I came back to the states in 2004 but its still sitting in storage. I recently bought a yamaha mx 800 and an m 80 so dont really need it.
Wow, I know this thread is old, but it's almost identical to the problem I am having with the identical amp.

I hate when a thread goes cold and there's no "okay everybody my problem is solved and the amp works great now" post.

I checked my rectifiers against one another and the read the same, so I assume they are both okay. There are a ton of transistors in this amp and before I go and start checking I want to make sure I do more obvious tests first.

help me please. :bawling:
I have developed the same problem. My HK Citation 22 blows one of its 5A fuses immediately on power up. With the help of this thread, I was able to identify that one of the rectifiers is bad. It is shorted across the positive and negative terminals. The other rectifier does not exhibit this short. Here are some questions on my mind right now that I would appreciate some help with:

-I’m confounded on how to proceed with finding a replacement rectifier as I don’t know it’s specs or much at all about rectifiers.
-I’m wondering if the amp will sound right with possibly two non-identical rectifiers. Should I consider replacing both to have a matched pair?
-I’ve read that when rectifiers go, they take other things with them. How do I proceed to check things out?

Ed Williams
it will sound perfectly allright

but be on the safe side why dont you replace both ....

then again this particular thread has enough info to tell you that rectifiers in the particular amp fail quiet easilly ..... so go for something bigger .....

also even if the rectifier is off that doesnt mean that this the only poblem ...there might be more

also at this age of amp and also depnting how much heat and stress was placed on your amp you might consider a recaping ....

take a look at this and also check for upgrades in the forum ....small stuff here and there can make a hell of a lot of diference in one amplifier ....

given the oportunity you might also wana take a look at settings like bias and offset ....

check it out

Thanks for the info and the link to the giant how-to on vintage amps. I take it from that tutorial, that if i find a bad transistor that I'll need to replace them all. Wow, there is a lot of them in my amp. Do you have any advice for me on my biggest challenge of all? That is determining what rectifier will be an appropriate replacement. I don't really know where to begin as I don't know the specs of the original and I have not found anything on the Internet from searching the part number printed on it which is D5SB 40 73. One guy had posted a JPG that shows it. I'm new to diyaudio, should I make a new post to attract advice from lots of people, since this one is so old, or will that **** people off...making a new post on an old topic?

Ed Williams
very simple

first of all you need to verify what is the ac voltage that used to go to the rectifier

after that you may choose twice as much will not be a problem

then you need to calculate how many amps normally pass through this rectifier .....

for example 100 w per chanel amplifier means that consumes arround 200w of power to do that ( or more )

then use ohms law to calculate and you know how many amps pass by your rectifier .....

this information is actually useless for you since your target is to get a rectifier as big is possible at least twice the voltage and as many amps is possible on the specific package

also may be possible a mod to be done to install a rectifier of another package and use small pcs of wire to make the connections ....

in the specific package your previous rectifier was there is not much chances to find a rectifier that is more amps than the one you had ...

so mod it and it will happily work for another 100 years ....

the "manual" is the simplest approach possible this manual a simplified theory and quick guide is the go .....

regards sakis
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