Harman Kardon Five Twenty ?
- Thread starter cubdog
- Start date
cubdog
banging through drywall
HK guys, please give me some help. This receiver has three fuses, one for each speaker, and one to power up I think. It also has, on the back, three or four I didn't count, plastic covers. I removed one and found a RCA metal cap. I do not know what these are for. The receiver had a blown power up fuse which I replaced with one of the speaker fuses. It came on then immediately blew that fuse. Different sizes I think. This was in a pawn shop and they said they would sell it to me for $25.00 instead of $40.00. I believe Orion values this at $180.00. So what is this thing? Like I said it weighs a ton and there are no vents anywhere. Please help I would hate to let this get by if it is worth something. Thanks again.
cubdog
cubdog
mhardy6647
Lunatic Member
The plastic covers on the back (should be 4) are the output transistors. These are the "metal caps" you see under 'em. Since the outputs are on the back, and the chassis is their heatsink, h/k apparently didn't see the need for any vents. Blowing a fuse is a bad sign.
Manitoulin
A proud member of AK
I think the Orion price is OTL. I have a Five Thirty, which is similar to the Five Twenty, except it has AM and FM (The Five Twenty is FM only). I bought mine, in perfect shape, with wood case and owner's manual for $33. Others routinely go for less than $40 for working models, so $25 for a dead unit is still a bit much as far as I am concerned.
A quick check. If you have a digital voltmeter, make sure the unit is powered off, set the speakers switch to spkr1, and read the resistance across the speaker outlputs. If it reads 0 ohms be sure to reverse the leads to be 100% sure), one of the output transistors is shorted. This test is not absolute as certain amp designs will not show a short at the speaker leads even with shorted transistors.
The caps over the transistors are there to protect the transistors from being shorted to a nearly metal object. Unless you have experiance, do not remove the transistors. There are insulators and heat conductive paste that need to be installed properly. Serious damage can occur if the transistors are not mounted correctly.
I do not have a service manual, or I could help a bit more.
If the unit is in perfect shape, with wood case, offer no more than $15, IMHO. It will cost at least $30 for a service manual (according to online vendors), plus the cost to service. If you decide to pass, I would be interested in it, if you are willing to ship to me (all costs covered, plus a donation to AK).
Regards,
Joe
A quick check. If you have a digital voltmeter, make sure the unit is powered off, set the speakers switch to spkr1, and read the resistance across the speaker outlputs. If it reads 0 ohms be sure to reverse the leads to be 100% sure), one of the output transistors is shorted. This test is not absolute as certain amp designs will not show a short at the speaker leads even with shorted transistors.
The caps over the transistors are there to protect the transistors from being shorted to a nearly metal object. Unless you have experiance, do not remove the transistors. There are insulators and heat conductive paste that need to be installed properly. Serious damage can occur if the transistors are not mounted correctly.
I do not have a service manual, or I could help a bit more.
If the unit is in perfect shape, with wood case, offer no more than $15, IMHO. It will cost at least $30 for a service manual (according to online vendors), plus the cost to service. If you decide to pass, I would be interested in it, if you are willing to ship to me (all costs covered, plus a donation to AK).
Regards,
Joe
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