Harmon Kardon HK3270 broken?

[billsif]

As you may have read in a previous post, I bought a Harmon Kardon HK3270 stereo receiver at a thrift store for $20. It doesn't seem to be working properly:

I connected my computer's line out to the HK's Aux In and get no sound, also tried the Tape In and no luck either. There is a set of RCA inputs labeled "MAIN IN" and I tried those - very loud signal passed through and out the speakers, which I couldn't control with the receiver's volume dial nor with my pc's sound level. I quickly unplugged the RCAs from this input (and probably shouldn't have hooked it up that way in the first place). I noticed there is a very faint hum when you turn the receiver on.

Using the built-in FM tuner, there is a very faint signal getting to the speakers.

Could there be a simple fix such as a blown fuse I can replace?
Are there any other tests I should try?
What is "Main In" ?

Thanks,
Bill

[billsif]

Well, upon reading the PDF of the manual available on Harmon Kardon's web site

"Main In: These jacks are the input
to the HK3270’s power amplifier. Unless
an external power amplifier is used, the
jumper pins should remain connected
to the Preamp Out jacks"

I have no jumpers - can I simply connect a pair of RCA cables from the Main In to the Preamp Out?

Thanks!

[pdxotica]

My Pioneer receiver has a separable amp/preamp, and the jumper pins are just chrome steel wire.

You could probably fabricate some yourself using heavy bicycle spokes. Check the inner radius dimension of the jack, and get a couple stainless steel spokes of the appropriate gage.

Don't use the cheaper zinc/galvanized spokes. Splurge on this puppy. Worth the extra 13 cents.

Snip and bent to shape, and in a couple minutes you've got original looking jumpers again!

[billsif]

with no bicycle spokes handy (for now), can i use a pair of rca cables just to get this thing working? i dont see why not, i just dont want to damage anything...

[cademan]

That's exactly what your problem is! Yes, you can use a pair of RCA patchcords to connect to PRE-OUT to MAIN IN. Those jacks on the back of your receiver (PRE-OUT/MAIN-IN) give you more versatile use of your receiver. The pre-out jacks can be used to drive another separate power amplifier. Any power amplifier. The main-in jacks mean you can use another pre-amplifier to drive the power amplifier in your receiver only. There are many ways to utilize those jacks especially if you have more than one power amplifier or multiple speaker set-up!

[cademan]

Technically, the PRE-OUT/MAIN-IN jacks connect your volume, bass, treble controls, to the main internal amplifier.

[ccheath]

I have no jumpers - can I simply connect a pair of RCA cables from the Main In to the Preamp Out?

Thanks!

I have HK3480 and it has jumpers on them. My HK730 (vintage) is missing jumpers so I have RCA patchcord used as jumpers. They work perfectly.