That's a good idea using breadboard/veroboard type stuff. Depending on the print you can even drill/redrill the board and hard wire it in underneath.
It’s out! And I was lucky, it is like that 👍 Cleaned by thicker paper soaked in isopropyl alcohol..
Looks like pretty uncommon connection solution - the sidemost contacts are bridged by internal connector?
Oh excellent stuff 🙂 That should be be good to go then with a good clean like that. Do all the contacts look good?
Having the Service Manual, it should list the relay info in order to search for a compatable one.
And that's the first thing to do - get the Service Manual before tinkering around.
It makes the job of troubleshooting much easier.
As to cleaning, it's much easier to remove the spring, lift the armature out and get a better look at the contacts.
And that's the first thing to do - get the Service Manual before tinkering around.
It makes the job of troubleshooting much easier.
As to cleaning, it's much easier to remove the spring, lift the armature out and get a better look at the contacts.
"should" is the keyword 😉
This is what you see in SM:
- and I fail to match it with the contact layout in the first relay photo.
Probably label type from the relay cover would be handy also.
Edit:
Perhaps I have just not met one like this yet.
This is what you see in SM:
- and I fail to match it with the contact layout in the first relay photo.
Probably label type from the relay cover would be handy also.
Edit:
Perhaps I have just not met one like this yet.
Yes, I have downloaded the manual, thank you, also tried to do the bias adjustment, first time ever 🙈🙂
According to manual, I did adjust the bias to around 6.6mV for both channels, I think successfully 😉
When I tested the bias before, it was only about 2-3mV, now it is about 6.6mV.
While adjusting I did keep the amp on for a little while to stabilise, then I did adjustments, and when it fluctuated around 6.6mV, then a repeated the procedure on the other channel. Hope that was okay to do like that..
While adjusting I did keep the amp on for a little while to stabilise, then I did adjustments, and when it fluctuated around 6.6mV, then a repeated the procedure on the other channel. Hope that was okay to do like that..
Seems that it is even possible to buy a new relay should it be necessary:
https://www.euromaxx.nu/product/marantz-speaker-relais-relay-mslu-24vdc-24v-speakerrelais/
https://www.euromaxx.nu/product/marantz-speaker-relais-relay-mslu-24vdc-24v-speakerrelais/
Great, thank you! I think, except a few parts maybe, all the standard parts - transistors, capacitors shouldn’t be problem to source, probably even 2 ICs uPC1024H..
I have listened to the amp for a while, only through headphones though.
When the signal low, right channel disappears through distortion. For example the end of the song.
Or
When increasing the volume slowly from zero, left channel starts immediately. The right channel suddenly joins when volume pot around 8 o’clock, when at about 9 o’clock, both channels are stable already.
It is practically not possible to listen both channels at low volume.
Reducing volume below 8 o’clock causes the right channel to give up..
Perhaps pot is worn out, cause I have cleaned it a few times.
Or something else is there to investigate.
What would be good to try? Thank you.
When the signal low, right channel disappears through distortion. For example the end of the song.
Or
When increasing the volume slowly from zero, left channel starts immediately. The right channel suddenly joins when volume pot around 8 o’clock, when at about 9 o’clock, both channels are stable already.
It is practically not possible to listen both channels at low volume.
Reducing volume below 8 o’clock causes the right channel to give up..
Perhaps pot is worn out, cause I have cleaned it a few times.
Or something else is there to investigate.
What would be good to try? Thank you.
Before "trying" you should - at least attempt - to measure you amplifier.
If you start with the preamplifier section and take the signal from pre-out then a simple (external) sound card and RMAA (RightMark Audio Analyzer) software (free) will give you a visual and numerical starting point.
Also it will give you the baseline for comparison after you have completed the work.
Next there are (for me) two usual things to do without too much hesitation (problem with such old gear is that there is usually more than one underperforming component in them so it is frequently difficult to narrow down such a problem to just one component):
Not very good for signal.
Anyhow - you have to work and progress systematically - radomly replacing components is a bad idea.
If you start with the preamplifier section and take the signal from pre-out then a simple (external) sound card and RMAA (RightMark Audio Analyzer) software (free) will give you a visual and numerical starting point.
Also it will give you the baseline for comparison after you have completed the work.
Next there are (for me) two usual things to do without too much hesitation (problem with such old gear is that there is usually more than one underperforming component in them so it is frequently difficult to narrow down such a problem to just one component):
- replace all lytics in signal path;
- clean the contacts of sliding switches.
Not very good for signal.
Anyhow - you have to work and progress systematically - radomly replacing components is a bad idea.
Thank you, I got it up to minimal level. Before I will start asking some stupid questions, maybe there is some manual how to do it for dummies, like from basics..
I might understand that I will feed some signal to let’s say AUX input of the amp, and take it out from Preamp out rca sockets into computer through external cheap sound card. I should have some old SoundBlaster.
But what will generate the signal is not clear to me, perhaps mobile app tone generator through some Bluetooth device into Aux, or will that be computer directly through 3.5mm socket to Aux rca inputs?
Then from preamp out it should go to external sound card, ADC converted internally and into usb input of the computer?
You see I am lost 🙂
I will do some research..
Forget about messing with the volume pot, except for a proper spray cleaning.
You'll never find a suitable replacement today - volume pots with 'loudness taps' are no longer made.
And it's a shame, a deterrent to keeping older amps in shape.
I blame the eccentric audiophile crowds - starting their complaining that 'loudness' isn't needed, nor are tone controls.
Bleh!.... all nonsense.
You'll never find a suitable replacement today - volume pots with 'loudness taps' are no longer made.
And it's a shame, a deterrent to keeping older amps in shape.
I blame the eccentric audiophile crowds - starting their complaining that 'loudness' isn't needed, nor are tone controls.
Bleh!.... all nonsense.