Worth fixing? Denon DRA-550...

I have an old Denon DRA550 receiver in which the right channel has died. Is it worth fixing this thing or do I just pilfer it for parts. They are 50W p/c so I thought I might be able to use the transformer for my chip amp.

I tried to find a service manual for it to see what size the transformer is and only found one at servicemanuals.net but they want 17.00 for it and I don't want to pay for one if it is going to the big graveyard in the sky....

Cheers
Bruce
 
the specific amp worth working with... basically is well made as is it will need recaping and some service and generally this is something worth doing in an allready well made machine

cost of upgrading such a machine can be very low if done diy but will cost a lot if done by expert .In any case there is a very good potential for this machine to be repaired and upgraded and with a life expectancy of at least 30 years .

on the negative side of this amp is the internal wiring that will produce crosstalks if more than one active source is conected and the preamp section that complicates signal a bit more

schematic is available if you wish to have it just e mail me
and here is some info regarding repair procedures and trouble free start up http://www.diyaudio.com/forums/solid-state/136261-vintage-amplifier-repair-upgrade-manual.html

kind regards sakis
 
Hi sakis

Thanks for the insight.... I think there is a possible better future for this amp yet. I am definitely up to giving it a go, heck, if I stuff it up I'll use it for parts :)

The circuit diagram would definitely be handy, will have to try and source a service manual to see how to pull it apart safely (read put it back together afterwards :)).

I cracked it open just now and found some blackening on the board, focused around cap C564 & resister R586 (or could be 566). The resistor has come away from the board which wouldn't help much :) plus it is blackened.

I'll send you a PM re your email and give you mine too. Thanks again for the offer.

Cheers
Bruce
 
Thanks for the email, got it and have been looking through the docs.

Have run into a roadblock at the moment. I have confirmed that resistor R566 is toast but cannot find it on either the parts list or in the schematic. It and it's neighboring cap C564 shows on the board layout diagram however which I find strange. It's 1:22am now so I am going to get some sleep and look again tomorrow.

My plan was to replace the resistor and then do some measurements to see what is happening as a starting point but until I find the value of the component I am stuck!

Cheers
Bruce
 
Tone Control - Frequency Response

I am looking for a test review, where I can find a diagram of the frequency response by various positions of the baxandal tone control.

Stereophile dosn't release this diagrams of that model.

For me the most important thing is the center frequency, from where the high frequencies are enhanced by boosting the treble.

Thank you for an advice to such magazines, where this model was tested.
 
Hello T

+-8db at 100Hz for the low +-8db at 10khz for the high

Quoted from the service manual

sorry for my not perfect phrasing.
I write:
..."from where the high frequencies are enhanced by boosting the treble"
but I mean:
..."from where the high frequencies and low frequencies are enhanced by boosting the bass and treble"
This frequency is those, where is not any increase/decrease (center/pivot frequency).
The lowest and the highest cut-off frequency isn't important for my case.