Repairing my 22AH384

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Repairing my 22AH384

Messagede suretrak » 10 Oct 2010 20:28

Following my report of repairing my Philips Amplifier 22AH384. A repair always starts with searching the Internet for the service manual. I found the service manual for the 22AH384 on this forum, asked for a password which was sent to me very fast, and downloaded the service manual which was of a very good quality. Thanks again for the service. I promised to place my report on the forum when the repair was finished.

But first of all I will introduce myself. I am a Philips audio collector from the period late sixties until the early eighties (when I was younger :guitarra: ). I am living in Holland. I started collecting four years ago after I bought a Philips tape recorder, N4515, which I wanted very much but could not afford at the time it was sold in the hifi audio shops.

My wife and kids where happy :smile: for me on that moment and where glad that I started a new hobby that, as they said, was a innocent one. In the Meanwhile they changed their opinion about that a little because my collection has became a little bit bigger than only the N4515.
I like to collect complete sets of one model or period. For example I have a set which consists of: 22AH551, 22RH651, GA209S, N2510, N4450, N6719, N6302, EL1979, and (4x) 22AH544, and is in good working conditions.

01 setje jaren 70.jpg
my set, early seventies
01 setje jaren 70.jpg (50.2 Kio) Vu 15768 fois


When I started collecting I had no experience at all with electronics, I am a construction engineer working for a contractor who lays underground pipelines for gas and water transport. So the world of electronics was a new challenge for me. But with the help of other collectors and enthusiasts on a internet forum like this in Holland I found my way and learned a lot during the last four years. If someone is interested, the internet forum is called MFBfreaks.com. Most of the topics are in Dutch, like most of the topics on this forum are in French, it is a pity that I can not read French because when I look at some of the pictures on several topics it must be very interesting.

So, enough about myself here is the story of repairing the 22AH384. I got the amplifier for free from someone I bought a Philips tuner 22AH186. The amplifier did not produce any signal at the connections anymore was his message. I was very pleased with it.

When I came home, I connected a Philips CD player, CD210, two 22AH544 MFB loudspeakers and switched it on. And….., there was the sound of Pink Floyd coming out of the speakers………, for a short moment, suddenly a lot of scratching, a click of the relais switch, followed by…………silence. A little bit disappointing, but what could I expect, the owner told me that the amplifier was defect.

I opened the amplifier, and as always I made some pictures, this is how it looked:
001 how it came in.jpg
this is how it came in
001 how it came in.jpg (131.86 Kio) Vu 15770 fois


This was the moment I realized that I needed the service manual, and started my search on the internet and found it at vintage-audio- laser.com

At first I thought that it could be the reais switch (hey…don’t forget that I am a construction engineer). I soldered out the relais switch and cleaned the contacts with contact spray on a piece of paper. And as you can see on the pictures, that it was not done for nothing.

02 cleaning the relais switch.jpg
cleaining the relais switch
02 cleaning the relais switch.jpg (85.29 Kio) Vu 15770 fois


I checked the relais switch with an external power supply if it was still working, and it was. I soldered, the switch back on the print, switched the amplifier on…….., and as you guessed, nothing happened.

Ok, what is next, taking measurements, that is what you always do at first. I made some A3 prints of the schematics and step by step I checked the values as noted on the schematics. I started from the power supply onwards through the amplifier. And on a sudden moment the measured values were not correct. I found some differences between the values on the connections of the main amp driver unit left and right. (see the picture of the part of the print layout at the backside)

03 measurements driver units.jpg
taking measurements
03 measurements driver units.jpg (121.06 Kio) Vu 15770 fois


My conclusion: there must be something wrong with the main amp drive unit of the right channel, the values for the left channel, matched acceptable with the values in de service manual.

I took out the print of the drive unit for the right channel, switched the amplifier on………., and yes there was the click of the relais and the amplifier produced its sound again, only on the left channel of coarse.

To be sure it was only due to a defect on the print of the right drive unit, I took out the drive unit for de left channel also and checked the values of the amplifier. The left and right channel values were acceptable equal. So it must be on the drive unit print. Probably some of the transistors.

I decided to renew them all. But, that was not as easy as I thought, my local supplier did not have the 2SC2363 and the 2SA942. he also did not have the substitutes as mentioned in his “substitute master guide”, so I had to figure out if there were any other substitutes for the transistors. And that was new for me.

First of all I studied a little on the internet about transistors. Then I searched for substitutes on the internet, and I found several cross reference lists with substitutes. I put the substitutes in an Excel Matrix, determined which of the substitutes could be delivered by my local supplier. Then I downloaded the data sheets of those substitutes and put there characteristics in an other Excel matrix to compare them. Based on the data in the matrix I made my choice for a good substitute. I have made some screen prints of the Excel matrix to get an idea.

04 possible substitutes.jpg
possible substitutes
04 possible substitutes.jpg (110.35 Kio) Vu 15770 fois
suretrak
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Re: Repairing my 22AH384

Messagede suretrak » 10 Oct 2010 20:45

Comparing the characteristics (1)
05 substitutes 2SC2363-01.jpg
Comparing the characteristics (1)
05 substitutes 2SC2363-01.jpg (39.86 Kio) Vu 15768 fois


Comparing the characteristics (2)
06 substitutes 2SC2363-02.jpg
Comparing the characteristics (2)
06 substitutes 2SC2363-02.jpg (54.68 Kio) Vu 15768 fois


For the 2SC2363, I took the 2SC1841 as a substitute
For the 2SA942, I took the 2SA970 as a substitute

Last Saturday I bought all the new transistors for the main amp driver unit and soldered them on the print, put the print back in the amplifier, connected the CD210, the MFB-544 and switch on the 22AH384, and……………………………….YES…!!!!! it is working again. It sounds good, the amplifier has played during the whole day and there was…., and still is nothing wrong.

The repairing and the result
07 its working again.jpg
The repairing and the result
07 its working again.jpg (49.17 Kio) Vu 15768 fois


After repairing the amplifier I cleaned it at the inside and the outside. The aluminum front is waxed with car wax and looks very nice again. There are only some light scratches on the top that proofs that this is a piece of audio equipment of almost 35 years old.

After cleaning
08 cleaning.jpg
after cleaning
08 cleaning.jpg (64.75 Kio) Vu 15768 fois


After the cleaning I rebuild the amplifier and enjoyed its sound and its looks. I made some last pictures of the results, and I think I may be proud of it.
The final result a beautiful 22AH384, in full glory

09 special thanks.jpg
with special thanks
09 special thanks.jpg (49.64 Kio) Vu 15768 fois


My next project will be the tuner of the same model series, the 22AH186. As I already told before I always try to collect a complete set of the same model. I still have to find a cassette deck and a pickup to complete this set. I already have the tape recorder N4420. I don’t know for sure if there already was a CD player at that time.

Thanks to all of you again, I could not have done it without the service manual that is for sure..!! I hope you will enjoy reading my report.
suretrak
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Re: Repairing my 22AH384

Messagede daniel-12 » 10 Oct 2010 20:54

Beautiful work :thumbsup:
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Re: Repairing my 22AH384

Messagede art-of-entertainment » 10 Oct 2010 20:55

waouwwwww :love: :thumbsup:
thant you for your post :jap:
congratulations !!! nice job :bravo_mon_pote:
...aoe verra...
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Re: Repairing my 22AH384

Messagede Tichu » 10 Oct 2010 20:55

Welcome, and congrats for your repair job !

You must know the dutch site http://www.mfbfreaks.nl/ ?
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Re: Repairing my 22AH384

Messagede stan » 10 Oct 2010 21:35

Suretrak is a member from Mfbfreaks, according to what he says in the first post above (and in recent PM's :monpote:)

First of all, thanks a lot for coming back here and taking the time to report this excellent job!! By the way, congratulations for your beautiful Philips stuff!

Then, I must admit that I am surprised you didn't connect an old Philips CD player to your Philips System, though there were no CD players when your Philips amp hit the market. IMHO, a philips CD100 would be a great choice :thumbsup:

Kind regards :jap: :jap:
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Re: Repairing my 22AH384

Messagede suretrak » 07 Nov 2010 19:48

Thanks for all the compliments, it is nice to see the enthusiastic reactions from all of you :jap: :jap: .

Sorry for my late reply :ic5: , but I have bin busy, with several things lately, I will be moving in a couple months, and there was less time left for my hobby's

a philips CD100 would be a great choice


A CD-100 would indeed be very nice :dignus: unless the timeline does not match with the 384. But to find a CD-100 in reasonable state and for a reasonable price will not be easy. In Holland they ask a fortune for it and you how Dutch people are :0906: :0906: :ic11: . If there is someone on this forum who wants to sell a CD-100 for a reasonable price sent me a PM please.

You must know the dutch site http://www.mfbfreaks.nl/ ?


The site of MFBfreaks.nl (not .com) is also known by me, as well as several other sites on witch you can communicate with audio lovers of all kind.

Many people on those sites, like you, have helped me al lot in the past.

My next job is a 22AH799, looks quite complicated inside :ic30: and has one problem I haven't figure out yet what it is. If you are interested in the story, let me know, then I will place the report later when the job is finished. It could take a while as a result of the moving to an other house, but I always keep my word.

If someone already has some tips please let me know.

Greetings,
Suretrak, Holland
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Re: Repairing my 22AH384

Messagede Tichu » 07 Nov 2010 21:06

Suretrak,

I also have a 22AH799 in repair state (amp works fine, but the tuning wheel is not working)
So yes, we would like top hear about your progress on this nice piece of gear, one of my favorites from Philips.
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Re: Repairing my 22AH384

Messagede suretrak » 07 Nov 2010 22:43

(amp works fine, but the tuning wheel is not working)


My 799 has the same problems, clock works, presets works, but no reaction on the tuning wheel. MW keeps on 520, LW keeps on 150 and FM keeps on 87.50.

I just have (ten minutes ago) placed the problem with my 799 on the Dutch forum and will wait for the answer(s).

If the problem with my 799 will be solved there will be a good chance that the problems with your 799 also will be solved.

I will keep you informed..!!
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Re: Repairing my 22AH384

Messagede Tichu » 07 Nov 2010 22:49

Thanks.

I believe the wheel has optical detector instead of driving a real variable capacitor.
It may be a simple issue of the logic behind the detectors.
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Re: Repairing my 22AH384

Messagede suretrak » 07 Nov 2010 23:32

I believe the wheel has optical detector instead of driving a real variable capacitor.


Thats right, it has indeed an optical detector, I checked it already.

It may be a simple issue of the logic behind the detectors


I studied the service manual, and there is a lot of logic behind the detctors :ic30: :ic30:, that is not so simple for me :icon_frenchy:. But I am sure that the members of the Dutch forum know how to help us.
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Re: Repairing my 22AH384

Messagede Tichu » 24 Oct 2015 21:08


Ce forum est désormais fermé. Si vous souhaitez y participer, rendez-vous sur le nouvel espace de discussions :


http://vintage-audio-laser.fr


Il s'agit d'un nouveau forum, donc les comptes actuels n'y sont pas reportés. Vous devez vous ré-inscrire pour y participer.

Veuillez lire votre message privé de bienvenue dès votre arrivée.


Merci
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