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Restoration of a 2220B in a very bad state.. need some help if possible.

bonsaichop

bonsaichop

Member
Restoration of a 2220B in a very bad state.. *update* all problems fixed!

Hey All,

Long story short I saved a 2220B that couldn't be sold at a flea market from the bin, thinking that it would be a fun weekend project I never realised until I took it home how much a rescue would be needed! There were colonies of spiders living in every nook (even inside the knobs!!!), it looks like it was sprayed with mud and rain for some time and someone had sprayed everything with WD40! And when I say every I mean everything! It was dripping out more oil than my car!

Here are some pics, before and after just so you have have a look at the state it was in before I go into detail about my problem

Original state less the spiders/bugs:


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Thats what i've been doing wrong with my speaker connections all this time! They belong on the signal needle lamp post!



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WD40.. everywhere!
How does it even get under the power junction?!


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And capacitors cannot be fixed by WD40


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Proof.. that's supposed to be 6800uf


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Transformer before:


After (sanded and repainted):


The main chassis was in such an awful state I had to take the whole unit apart to get the chassis out so that I could clean it up with an steel brush angle grinder.



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Seing all the boards here only held by their wires kind of reminds me of a person with no skeleton!



And the finished result: All boards cleaned, all caps replaced, pots and sliders cleaned, chasis repainted with high temp paint, and rear speakers replaced with binding posts(temporary fix).



The bad news when I got it was that nothing worked. Powered it on and nothing happened, lights went on, but couldn't get any life out of the VU meter, no output to speakers and nothing. I decided that I'd clean it up, do a full cap replacement before I really dove into the issues.

The good news was when I fired it up, everything came to life! FM/AUX/Tape and phono were great, tone control was fantastic, all the buttons did their job. Voltage across speakers is about 0.1mv and bias is perfect on 20mv But....

1) I can't get any sound from AM. I can tune for stations and the VU meter indicates that it is picking up some stations, but there is no sound coming out of the unit. Fixed! See post #13

2) There is a bit of sound bleed over on the inputs. If I have my iPhone plugged into AUX and playing, if I switch to phono/FM/tape/AM(yes even on the AM that does not work with it's own input) i'm not sure if I can shake this one.Fixed.. enough! See post #13

3) This is the one that is bothering me a bit, the right channel has a hiss that gradually gets louder regardless of the volume or balance change. This is happening with both headphones and speakers on all inputs. I'm assuming it has to do with the power amp board, however if someone could point me in the right place to look it would be much appreciated. The design schematic in the service manual and I have been pretty close the past couple of days but I can't get my head around this one. Fixed! See post #12

Anyway, I hope you kind people can help and I hope you all enjoy the restoration pictures! There's only a couple of cosmetic things to complete, adding of new feet as there were none and a rectified LED upgrade like I did with my 2275 in another post.

Cheers!
 
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Thanks for the pics. The most fun I've had all day. :P

This project must have been really great. Such an airy and empty receiver to work on.

Too bad about the problems. The hiss is probably caused by a bad transistor in the pre-amp.
 
Ruxman said:
Thanks for the pics. The most fun I've had all day. :P

This project must have been really great. Such an airy and empty receiver to work on.

Too bad about the problems. The hiss is probably caused by a bad transistor in the pre-amp.
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Thanks, i've got plenty more pics if anyone wants me to post them up, quite handy when re-assembling units to have as many as possible! The 2220B was a breath of fresh air to work on after spending close to 2 weeks completely rebuilding an abandoned 2275. So much space in this little beauty and such a clean layout.

The problems aren't too bad considering the state it was in when I first started. I guess I should probably start checking the voltages of all the transistors and compare them against the schematic to see if anything really sticks out.

Thanks!
 
Not good enough!


...... Just kidding. :D I think it's a stellar job you did. Gut it completely. Clean thoroughly and reassemble. What stands out to me is the transformer. It appear that you worked well around the sticker. It actually look like you got a new sticker on the repainted transformer. :thmbsp:
 
Nice work! I'd be nervous to take apart a receiver that much. Looks like you really put alot of effort into it.
Doesnt it make you feel good afterwards when you save an old piece of history.
 
Wow, nice job! I'm about to start my restore on a 2220B as soon as my parts arrive.
I really like how you painted the transformer also. Did you replace the stIcker or take off?
I want to clean the chassis also, did you have to disconnect the wires to each board or did you take them all out still attached?
 
Beautiful rescue work here, and great pics. I have 2 2220B's and they sound fantastic. I actually have a spare one for parts, LMK if you need anything since you have come so far on this one.
 
Thanks for all the replies :thmbsp: makes any restoration more the worth while!

ccheath said:
Not good enough!


...... Just kidding. :D I think it's a stellar job you did. Gut it completely. Clean thoroughly and reassemble. What stands out to me is the transformer. It appear that you worked well around the sticker. It actually look like you got a new sticker on the repainted transformer. :thmbsp:
Click to expand...

I must admit I didn't actually 'work around' the sticker, more so used a technique used in removing warranty labels.. don't ask :)

The transformer is first taken out of the unit, from it's binding posts as not to effect the wire wraps. Unless your unit has been upside down for most of it's life the bottom and mid sections should still be in great shape. The mid cover is actually painted with what appears to be an epoxy enamel so there's no need to repaint, just give it a good clean. The top cover is then removed by taking the nuts off from the bottom, then lifting the screws out. Don't trying and undo it by turning on the screw heads, it doesn't do anything.

Once the cover is removed, and using a hair dryer and non contact thermometer, the sticker is heated to about 50 degrees centigrade. I've found that any more past about 70 degrees and you can cause potential damage to the stickers but 50 is enough to soften the adhesive. A thin and very sharp blade is then used to lift one side of the sticker, then you can lift the rest off by hand.

Then immediately flatten the sticker on a smooth surface, I use a spare cutting board as it won't 'stick' on so well and is easy to take off without reheating the sticker.

The cover is then sanded back with an angle grinder with a steel wire brush head and then repainted using several coats satin black rust guard spray paint. The satin paint makes for a better match against the sticker than a gloss paint.

I'm going to do a 2275 transformer next so I'll take a full set of pics and write up a guide when I do that one. Below is a pic of the transformer with the cover off.



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morseguy said:
Nice work! I'd be nervous to take apart a receiver that much. Looks like you really put alot of effort into it.
Doesnt it make you feel good afterwards when you save an old piece of history.
Click to expand...

It really does, for several years i've been doing vintage computer restoration from the 70's and 80's and only in the past couple of years I have been doing audio gear. There's something magic about bringing one of these beauties back to it's former glory especially after years of deterioration and to hear them sing is wonderful! :)

LoTek said:
Wow, nice job! I'm about to start my restore on a 2220B as soon as my parts arrive.
I really like how you painted the transformer also. Did you replace the stIcker or take off?
I want to clean the chassis also, did you have to disconnect the wires to each board or did you take them all out still attached?
Click to expand...

See above re sticker

I was quite reluctant to do the chassis removal but in the state it was in I had no choice. It was like doing a vintage car's panels up but leaving the frame to rust. My intention started with lifting each board up and angling them through each hole. The FM P200 board and transformer had to be removed there was no choice in that matter, the P200 board is screwed on 4 brass posts and all the wires go through a hole to the underside. The rest did go according to plan, the P700 amp board was a bit of trouble and I had to take off it's large 470uf cap mid process because it was just too tall. The relay was also giving me some issues due to it's height.

Once I had gotten everything out (see the pic in my first post) I realised that there was that much build up of dirt and muddy water on the boards that I had to remove each one and clean them individually. Once again, desoldering off the binding post as not to interfere with the wire wrap.

If your unit's boards are in good condition you can just leave it at that without disconnecting the boards and then slide each one back in when putting it back togehter. Not for the faint of heart!

When doing work like this take as many pictures as possible! I took close to 100 photos detailing everything I did so I could retrace my steps. I also printed 2 copies of the service manual so I could refer to the component list and to the board references at the same time. And most importantly write down where every wire goes! These details will save you a lot of headache if you run into any trouble. I also bunched the wires of each section with colour coded cable ties. When I ran out of colours, I put markings on each so I knew which cables belonged to which board.

Below as a couple of more pictures for your viewing pleasure, the first 2 are mid way the chassis disassembly, the next is when I was putting it back together (you can actually see a blow up photo of the power junction which I was working on at the time on the computer. It really does come in handy taking photos! And the last picture are my wiring notes from my printed service manual, to give you an idea what I mean by 'writing everything down' :)



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patfont said:
Beautiful rescue work here, and great pics. I have 2 2220B's and they sound fantastic. I actually have a spare one for parts, LMK if you need anything since you have come so far on this one.
Click to expand...

Thanks :) Actually I am short 2 things, the Dolby button cap is missing and the sitch looks to have its end snapped off. The button works and I can bore it out and put a new stump but I'm short the button cap. Also the balance slider doesn't 'click' in it's centre position. I'm not sure if that is specific to this model, but on others I've worked on there seems to be a 'click' in that centre spot.

If you could help out with either one of these parts please send me a message happy to pay for everything but lets leave that to the PM :)



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Wow that was a long post!
 
Nice restoration! I've never had a receiver apart that far, bit frightening to see all the guts on the bench!
 
Jailtime said:
Nice restoration! I've never had a receiver apart that far, bit frightening to see all the guts on the bench!
Click to expand...

Thanks! It is a bit daunting seeing all the 'guts' floating around like that but if you plan it properly and note everything down it's not that bad.

Today was an adventure, the plan was to 1) Do a LED replacement 2) Add bypass caps to the filter caps 3) try and work out the problems I had in the first post.

Well I got all the LEDs installed. 12 blue LEDs, 2 red and one orange for the dial. Installed everything, worked beautifully, then added the bypass caps, no explosions there either, but then when I went to start working out that hissing issue, I plug my headphones in and there's no sound at all.. from any inputs.. huh?!?!?!

After an hour of prodding around and undoing the upgrades I had done earlier I established that power was good, and power was flowing to the 80% of the transistors that i had tested on the board the only ones I didn't test were the hard to get ones on the P700 Amp board. There were no bad contacts, and there were no shorts. So what gives?! I started to take the P700 power amp board out so that I could check there were no bad contacts on the underside which is connected to the heatsink when I just remembered a thread on AK about someone else having no sound issues due to the safety relay.

But this couldn't be, the relay was clicking just fine and when I was giving it a not so gentle tap while working out the issue I still had no sound. Well I thought it wouldn't hurt to take it apart anyway and give it a good clean. Low and behold after doing a continuity test while it was hooked up to my regulated DC power supply, it was clicking but not contacting! Quick fix, sanding each of the contacts and deoxing the contacts aswell. Put it back in... woohoo! Sound! :thmbsp: Still no AM though :(

So with that back in place I went on to connect the LEDs up again, I postponed the filter caps until I worked out the rest of the issues.

Next up, that damn hiss on the right channel. After some of the feedback and some pondering I came to the conclusion that because it's gradually getting louder even with the volume set to 0 i'm probably looking at a failing transistor somewhere along the preamp or amp section. I double checked the bias and that was all good, so out came the freezer spray and after letting the unit warm up for an hour, one by one i went through all the transistors.... but i couldn't find the issue. Back to the damn schematic! :tears:

Then I realised, what about the tone amp board?! Flipped the unit over, even though i had the underside of the tone amp board facing me, I figured there would be enough thermal conductivity to cool a transistor down. Sprayed the whole board and still nothing.... a few seconds later it went away! That was it!!!! Took the damn faceplate off yet again, got the tone board out and tested each transistor. It turned out to be one of the 2SC1328 transistors. A quick look showed I can replace it with the fairly popular BC550 transistor, but I couldn't order it online for next day delivery so I'll just pop into the local Jaycar(aka Aussie version of old school radio shack) and get some tomorrow.

So the todo list for this unit for tomorrow is:
1) Replace faulty 2SC1328 with BC550 (any objections or suggestions for a better replacement?)
2) Re-install bypass caps. I'm using these. Would they be alright? I have plenty on hand extra. I also have some Vishay x2 1uf 275v smoothing caps if they would be a better fit?
3) Have another stab at the semi functioning AM section and try and work out this sound bleeding issue.

Anyway more pictures of the before and after LED mod. I used rectifiers in this one aswell to stop the pulsating. Also a teaser on my next restoration project (Marantz/Esotec PM4 Class A amp :D:D)

Original lights:


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LED upgrade:


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I tried to get the lighting to represent the LEDs best but its so damn hard even with a DSLR and a $1.2k lens! The result is a beautiful uniform blue slightly darker than ultramarine blue. It looks sublime! Especailly with the nice orange dial. Offsets the blue perfectly.

And lastly the teaser.. :P I paid a little too much for this one, it was supposed to be working but there's barely any sound out of it, but i'll be doing a full rebuild on this beauty!

Stay tuned!



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Problems solved! Woo!

Well today was quite a pleasant day! Spent a couple of hours on the 2220B and got everything worked out. :banana:

Replaced the faulty 2SC1328 transistor on the tone amp board with a BC550, had to get very creative with the legs because the 2SC1328 had the legs as ECB but the BC550 was CBE. No issues though, fired the amp up and no more hiss! First problem out of the way!

Next up was the non functioning AM. had another close inspection of the AM board, then face-palmed myself as I realised the AM output was reversed. effectively grounding the AM board. Easy fix, reverse the binding posts. Sound was coming out of the AM board but it was very faint. Looking back at the schematic there were only 1 IC and 1 transistor that made up that circuit. Looking at the troubleshooting steps it said that if you picked up pin 11 of the AM IC with an oscilloscope you should be able to see the pre amped signal. Low and behold there it was on the 'scope. When I changed frequencies it was changing. So the problem was not there. Next up was a 2SC644 transistor, tested the voltage outputs and the emitter was only giving out 3v instead of 8v. Aha! Replaced that and now my AM was working great! Two problems down! I'm on a roll!

Now the last issue, the sound bleeding, I've been doing my research and it looks like it's fairly common. There's a couple of fixes for various models but it didn't look like it was worth it. As a safe precaution though, I reseated the input selector switch and reseated all the grounding connectors. Also verifying that ground from the power cable was good. Overall a slight drop in the bleed but it's still there. I'm still quite happy! :banana:

The last 2 things to do were quick and easy, I added the 1uf 250v film bypass caps, and also adjusted the tuning string position as it was about 1mhz off on the display from the actual frequency it was on.

So in terms of functionality everything is good! It's sounding fantastic though I havn't given it a good run yet, i'm in the process of troubleshooting a 1122DC for someone so I have that constantly running in the background. I'll have new dummy load resistors and a distortion meter ($20 on eb*y!) next week so once i've got all that gear


The only two things left to do is to replace the feet, and sort out the cover/bottom plate. Both of these are is lackluster condition. I'm fearing I may have to repaint the top cover as the faux wood trim looks pretty beat, if anyone has any good ideas as to how to restore it i'm all ears.

Only 2 pictures tonight, first is the bypass caps I installed, second is a view of the top casing for any ideas on how to restore it.



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Hi,

I did not read everything, but this is REALLY GREAT work! Thank you for sharing! :beerchug:

PM send about the switch!

Jan.
 
Hi bonsaichop,

How's the 2220B? I am about to start my restoration also, just waiting on my Caps to be delivered. I'm going to use all ELNA Cerafine IIs except for one single cap that I had to substitute for a Nichicon. I also got 2 Sprague 6800 uF - 50v filter caps.
I didn't know about the bypass caps until I read your thread so I'm gonna go look for some this weekend. Did you use 1uF polyester?
Did you replace your Diffs? (I'm not sure what those are and where to buy them)
How about re-greasing the Amp transistors, I think I'll do that too.
I hope mine comes out half as nice as yours! ;)
 
LoTek said:
Hi bonsaichop,

How's the 2220B? I am about to start my restoration also, just waiting on my Caps to be delivered. I'm going to use all ELNA Cerafine IIs except for one single cap that I had to substitute for a Nichicon. I also got 2 Sprague 6800 uF - 50v filter caps.
I didn't know about the bypass caps until I read your thread so I'm gonna go look for some this weekend. Did you use 1uF polyester?
Did you replace your Diffs? (I'm not sure what those are and where to buy them)
How about re-greasing the Amp transistors, I think I'll do that too.
I hope mine comes out half as nice as yours! ;)
Click to expand...

It's run into a little problem, I was testing it for a couple of days and the hiss came back, it looks like the other pair of 2sc1328 transistors have gone bad aswell, so i'll have to replace them with BC550s' aswell. I'd love to replace all my units with ELNA Cerafine IIs but they're hard to get in Australia as it is and then to get them from overseas it all starts to get too expensive. I've found a couple of suppliers of the Panasonic series of caps and between them I can get all the ones I need. I'm very pleased with their quality and cost so they're the winner in my books.

I started trying to clean up the vinyl faux wood and it started to come apart! So over the weekend i'll be stripping it off completely and giving it a satin black spray.

I've been following a few threads on the bypass caps on these forums recently and after spending a day testing them with bypass caps on and off I have noticed a difference in the mid-high range but it depends on the music you listen to. Female vocals tend and instruments like saxophones tend to have the most benefit to this addition.

The caps I used are these: http://au.element14.com/panasonic/ecqe2105jf/capacitor-film-250v-1uf/dp/1744795

The dielectric is Polyphenylene Sulphide. I'm actually curious if anyone has any insight on using X2 suppression caps as I have about 200 of them in the 1uf 275v flavor. I'd assume that they're not really for that purpose and would probably impair the performance but I know they give one hell of a kick if you accidentally touch one that's been charged!

I'm pretty sure the 2220B doesn't have diffs if they're what I think you're talking about.

I actually had to look up what you meant by 'regreasing' lol! and yes I did clean all the thermal interface material with isopropyl and then put a new layer of silicone thermal grease then put the gasket back on the transistors and put them back in. with some of those transistors they have a thin clear film between the transistor and the heatsink don't forget to re-install that (put grease between both layers) depending on the design it may short out the transistor if you don't put that film back in place. I would strongly recommend that you do this, most of that stuff is dry and caked up and it will hamper the thermal conductivity between your transistors and heatsinks.

Good luck with your recapping, these units are a joy to work with compared to some of the higher WPC rated systems. the hardest part will be getting the tone board out which required the faceplate to come off but even then.. still a joy to work with!

patfont said:
Any way to get a close up pic of the bypass cap installation?
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Try clicking on the image below, it'll go to my flickr page which you can blow it up a bit more. The bypass caps pretty much go across the filter caps with each connecting to ground.


http://www.flickr.com/photos/66195499@N07/6027777315/ by Bonsaichop, on Flickr
 
Quick update, yesterday we had some sun so I took the bottom cover to my workshop and got busy with the wire brush angle grinder on it. Got the paint and rust off. Then gave painted it with a satin black rustproof enamel paint. In the end I gave it 5 coats on each side plus a satin clear coat hardener. The same stuff I used on the transformer. Great stuff, acts as a primer aswell. I'll probably be using the same paint for the top cover once I work out a way to get the old crappy vinyl off without damaging the aluminum cover.

Photo time!

http://www.flickr.com/photos/66195499@N07/6037986461/ by Bonsaichop, on Flickr

http://www.flickr.com/photos/66195499@N07/6038553018/ by Bonsaichop, on Flickr

http://www.flickr.com/photos/66195499@N07/6038000195/ by Bonsaichop, on Flickr

http://www.flickr.com/photos/66195499@N07/6038544390/ by Bonsaichop, on Flickr
 
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