My first project Philips 22AH684

[GlowBlue]

Hi!

Today i bought a broken Philips 22AH684 receiver.I hope i get it at home the day after tomorrow.There are 2 reasons i bought this one.It has a MFB outputs to drive the Philips MFB 587 i bought 2 weeks ago and it is broken so if i manage to recap and repair it i have it for the normal asking price but then like new.I found a service manual; https://www.hifiengine.com/manual_li...ps/ah684.shtml
Can someone see if this is a clear manual to work with?I ask this because if i watch repairing video's on Youtube there are many hard to read scematics what give experienced people trouble.Is this receiver and manual good start?

The next things will be a Marantz cd73 with a crackling fire on the left channel.You barely hear it but when the song runs out the sound is not good and noisy. Then the Philips 587 speakers might be up for a recap and the gaskets done.I'm not sure on this.They sound good but i think they can sound much,much better.The people i bought them from had them from new almost 40 years ago.So i guess it lost some quality in time.But first things first,let's start with the receiver.My budget is very low so i have to do it in steps.

The toys i have available are a very cheap soldering station from Lidl (parkside),2 cheap multimeters,a 10MHz oscilliscope (Telequipment D61A) and a €1 magnifier Is this good to start with or can i better look for other things before i start?

English is not my native language.I'll try to be as clear as i can but not have always the right words.

Leon.

[ekjdm14]

Hi, I can't comment on the service manual as I haven't registered on that site yet (although I may do soon and could look then).

As far as the tools go, [str]a cheap soldering iron might be a bit "fierce" for working on elderly printed circuit boards so I might suggest a temperature controlled soldering station (I use a very cheap and common Hakko 936 Chinese clone, I think it cost me £20 and has been very useful) [/str] but you're a step ahead of me with an oscilloscope, I have yet to build mine from a kit when it arrives!

What are the symptoms with the receiver, if it's totally dead then just the multimeter and magnifier will be good enough to start diagnosis.

Edit- forgive me, I missed your Parkside is indeed likely a temperature controlled station hence more suitable.

[ms660]

Philips manual also available without registration from Elektrotanya:

https://elektrotanya.com/philips_22a.../download.html

Lawrence.

[GlowBlue]

It is a Marantz 84 and not 73.Sorry i confused the numbers.The 73 i sold for too less knowledge

Lawrence i have the manual in good order.My question is,is it a clear manual to work with?Can i depend on it as a noob or are there triggers only seniors can read?
The symptoms of the receiver is or are one channel death but playing in mono on 2 speakers.

Leon

[GlowBlue]

This is the one.I called and believe this is a good and fair receiver for mostly the sending cost.I payed €30 total.If we can repair it together it is a good start in my new life as repairman
https://www.marktplaats.nl/a/audio-t...f4f8b9c5b7a618

This guy has some books on caps.I have no money,but should i buy it?

Leon.

[ms660]

Originally Posted by GlowBlue

Lawrence i have the manual in good order.My question is,is it a clear manual to work with? Can i depend on it as a noob or are there triggers only seniors can read?

The manual looks clear from what I've seen of it so far, you might or might not be able to follow the circuit...depends on your skill level or if totally new to the game your ability to learn.

Lawrence.

[GlowBlue]

Hi Lawrence,i want to learn it! I go learn it
https://www.youtube.com/watch?v=dKByc2LzoS8

[GlowBlue]

Is my scope good to do audio?

[Diabolical Artificer]

The amp part of the Philips receiver might be straight forward to fix, but the receiver part is something else again, being far more complex. Philip's also have a reputation for corkscrew thinking, with weird and wonderful circuits often used in it's products. So it is not a bit of gear I'd recommend for beginner's but who knows you may be lucky and find a wire loose or similar.

It might be misleading watching Youtube video's as regards how easy audio gear is to fix. There are quite a few "change a few caps and it works" type video's, some done by tech's who know what they're doing, some done by folk who haven't a clue, still, you have to start somewhere.

"Is my scope good to do audio?" No idea, what scope is it? Also to fix a receiver you need a scope and sig gen of a higher bandwidth, lot's higher than the AF range.

Good luck, Andy.

[snowman_al]

Morning all,
Just to explain the MFB Leon refers to is Motional Feed Back, one of those Philips 'corkscrews' ideas from a while ago.
So the Philips 587 speakers he has are 'active' with their own internal amplifiers.

The 684 receiver has attenuated outputs to drive the MFB speakers. (As well as normal outputs to drive passive speakers of course.)
My Dutch is poor, but google says it looks like the set he has bought functions except for one channel of the amplifier?

Interesting times to come...

Leon,
The manual is as good as you will get, actually quite good for Philips.
And I think you mean 'trust' = vertrouwen. (Thrust = stoot?)

Alan

[ms660]

Unless I'm mistaken there's at least one error on the schematic (Ref. CS61 490) It shows that the monitor switch contact numbers given on the far right hand side of the schematic for tape A and tape B inputs are contact 1 for tape A and contact 4 for tape B, the circuit (also the PCB layout) shows otherwise....contact 4 for tape A and contact 1 for tape B, the contact numbers given for the dubbing switch and the selector switch on the far right of that schematic agree with the circuit.....so far as I can make out.

Just thought I would throw that one in to avoid any confusion in any possible diagnostics using tape as an input.

Lawrence.

[GlowBlue]

Hi! Thanks for the replies.The receiver is fully working accept 1 channel.In mono it plays on both channels.Tomorrow i have it delivered and then i can say more.It looks very easy in Youtube video'si agree.For me it is not a problem if it takes some time.My goal is to learn things down the road.Safety is my first priority.I did not touch the scope yet because i saw in a video that it can be very dangerous with the ground.Tomorrow if i have the receiver at home i will take some pictures from the inside.
In The Netherlands most radiostations are changing to dab+ Is it possible to convert an old radio to that?

Leon.

[jamesperrett]

If it works in mono then the main power amplifiers must be working and the problem must lie in the preamplifier section. Do you have something that you can connect to the tape outputs to see if they work?

[Diabolical Artificer]

Might be a dodgy switch or dry joint if your lucky, first thing, open it up, give it a visual inspection. If your schematic has little sinewave's marked on it, it makes thing's easier.

Re your scope, as long as you connect the black lead to chassis or ground, your fine, that and don't exceed it's AC max.

"In The Netherlands most radiostations are changing to dab+" Bummer, dire DAB here in UK too. No, you can't convert it to DAB.

Andy.

[GlowBlue]

The receiver arrived! I quickly connected it with some headphones and it is playing very well.If i play with the knobs i do get stereo sound and a lot of noise.So i think the receiver is ok.I go first clean the potentiometers and i shall make some pictures from the inside.I bought also some handy books the seller had in his other advertisements.And he gave me some nice extra things
I only have some broken tapedecks at the moment.Is it ok to test the tape outputs with a tuner or cd player?

Leon.

[GlowBlue]

It is playing like new after cleaning it.All the noise is gone and both channels work perfect.The sound is beautiful.The sound with the MFB speakers is so much better then the speakers connected to a very good Denon pre-amp.Does anyone have an idea how thats possible?Is it the output voltage?I did not try all the inputs and outputs.Can i connect another amplifier or the MFB speakers to the tape out?
Tomorrow i start with the Marantz cd player.Any suggestions what to look for?There is noise on the left channel what you best hear when a song is playing out.

Leon.

[Diabolical Artificer]

Dog looks happy, did you give him one of the chocolates? : )

It looks a clean bit of gear and doesn't look like it's been got at; nice attention to detail too, EG caps across the bridge rectifier. Often a good clean of the switches and pots is all that's needed.

The MFB speakers are supposed to be good. Speakers connected to just a pre amp will sound crap, not enough power to drive them.

Why would you want to connect another amp to the tape outs?

Speakers to tape out - no.

As regards the Marantz, perhaps your best starting another thread, but in the main, give it a good visual examination, clean pots/SW's, it then gets a lot harder, but simply put, test voltages of the power supply first, then divide or break up the DUT (device under test) into smaller parts. EG CD laser assembly and diode board, processing, line amp etc. Easy also to Google "Marantz etc", see if they have common faults.

Andy.

[GlowBlue]

Hi Andy,jamesperrett asked if i have anything to connect to it to see if it works ok.Lawrence noticed a wrong connection in the tape section in the scematic.The speakers are active speakers so they need to connect to a pre-amp.This receiver has normal speaker outputs and also pre-amp output to drive these speakers.So i think it's strange they sound so much better on this receiver.The seperation between the 3 drivers is more hearable,in balance it looks.First i go test if i can find anything in the tape out of the receiver and then open the cd player.For that i will open a new thread.I don't think that is as easy fixed as this receiver.
The dog like it when i'm moving things arround.The cats too but i have to be very carefull with things like the soldering iron and when i'm opening up amplifiers.They want to climb into everything and mess with the tools and parts.Maybe it's better not let them in the room when i'm working on things.
Thanks for the help so far.I hoped it needed some simple repair so i could practice on it.But on the other hand i have lots of other things for repair.

Leon.