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Marantz 2230B Recap Project - Started

During the last days of RS I bought numerous packages of resisters, typically under 1K ohm size. In this example of the stereo LED, using a 500 ohm resister, selected here just for simple math, would that allow the LED to be 50% brighter than the 1K, or has it been determined that 1K provides a good starting point re LED control?

Although there are a few threads about chassis/board washing, could you elaborate a little more on your cleaning? Nice looking job!!!
 
Thanks! It has been fun and educational for sure.

Regarding the LED, I found the info from another thread, and I really like the results with the 1K resistor. If it were any brighter I think it might be too much like a spot light. With the current resistor it looks about as bright as the blue LED's in the front.

Here's the original thread about the LED (http://mail.audiokarma.net/forums/showthread.php?t=151829)

Regarding the chassis cleaning, I did the following:

I originally cleaned what I could with 90% alcohol and de-fluxed the back of the boards with the alcohol and an old toothbrush. I rinsed it a lot with clean alcohol as the flux makes a mess. To clean up everything else after that, I did the following:

  1. Place the unit on the garage floor sitting on some towels. Misted the insides with simple green cleaner, being careful to not get too much into the potentiometers on the different boards.
  2. Used a soft bristle 2" paint brush to lightly scrub the boards being careful not to bend caps and other things. Detail work around board edges with the toothbrush.
  3. Stood unit up on one end to let everything drain. Misted with distilled water several times to get the simple green out of there.
  4. Used compressed air to get the water out of the cracks (30 psi max on the compressor).
  5. Used a hair dryer to finish drying up the unit.

I ended up letting the stereo sit for a day before power up since I was still waiting on parts and doing some re-capping, so I was ensured it was all clean and dry.
 
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I also realized I didn't share photos of the completed tone board. I used wima films for the nonpolar caps, and Elna silmics everywhere else I could. There are few nichicon fine golds on there as well. As i mentioned in another thread, I found a silmic cap I had put in backwards. It was causing the voltages to jump and the left channel to be very distorted. I'm finding that it helps a lot to take before pictures to reference to make sure the new caps go in the right directions. It's even more helpful on other units because some of them have silkscreen errors and the factory caps are put in "backward" from the beginning.



Also important was building a compact dim bulb tester. I had a lot of the parts already laying around so it was a matter of just going to Home Depot and grabbing a nice plastic double gang box.



Dim bulb was a great way to power up during testing to make sure I didn't fry anything between each board recap and test. I built mine from this thread as refernce: http://www.audiokarma.org/forums/showthread.php?t=465423
For the parts I used a grey double gang electrical box, switch, outlet, 2-gang plate with outlet/switch, a 3/4" PVC end cap, some pieces of romex wire, and an old PC power cord. I drilled a hole in the pvc end cap, stuck the cord through it and tied a knot to keep it secure. The rest of the wiring followed the diagram in the referenced thread.
 
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Here's a shot of the underbelly after everything is all ready for closure.


The faceplate all cleaned up and reinstalled:


Top back on:


And finally hanging out with it's sony ES CD player friend:


It was quite the fun and interesting project. I didn't end up re-capping the AM/Front end yet. I figure I can always go back and do that in the future if I think it needs to be done. The other thing I may end up doing is replacing the amp board trimpots with some more precise bourns units.
 
Awesome job! I'm going to recap my 2230B and really appreciate the parts list and detailed instructions. I've done quite a few NAD units, but was intimidated by the Marantz for some reason.
 
Nice work. Enjoy.

I like the looks and performance of the desoldering tool. Wick isn't cheap and after a few years, a person might be able to easily justify the expense.
 
Nice Rebuild, great info and best of all the unit is in beautiful condition, many are not.

I'm Jealous. I've read numerous places of people picking these up cheap at Thrift Stores, Goodwill's Estate sales, SA's etc. But after 2 months of driving to these places locally here in St.louis, nothing. Figured with the gas and time spent I'd just buy an overpriced one off E-bay.

I re-capped a 2220B recently and purchased a pre-packaged kit of Caps on E-Bay. The outfit that sells them says not to replace the caps on the Tuner Boards without having test equipment. They don't even includes those Caps. Does anyone know if that's true? Just Purchased a 2230B and going to Re-furbish it. Thanks for any help. First time poster at AK
 
Cowdog
I noticed that you bought 8200 mf filter Caps. The ones in my 2230B are 6800 and the manual calls for the same thing. Can you advise?
Thanks
 
Welcome to AK!

Read, Read, & Read. Lots to tell you, but i will just say the basic stuff, Like

Build a simple Dim Bulb Tester
Do one board at a time and Test the unit each time.
write down everything on paper before unsoldering, Like,
cap direction and value
Wire colors, if you are removing wires
Unsolder the whole pin, if removing wires.
Use cloth over the socket used to remove the face plate.
Use a thick pad on your work bench to protect the receiver from getting scratched.
Use a variable temp solder station. 400 degrees works well for me.
Use good solder. Kester .030 thick.http://www.amazon.com/Kester-Rosin-Core-Solder-Spool/dp/B00068IJPO

Take before and after pictures.
Use good heatsink paste. No silver stuff.
CleaN your work with 100% rubbing alcohol, and drink good beer, not the cheap stuff.
don't get 100uf mixed up with 100v. :D
Unplug it before you work on it and adjust everything to spec,(p/s voltage dc offset idle current) according to your service manual. do not use dbt when adjusting voltages.

Upping your filters to the numbers you mentioned is fine. Just make damn sure you put the pos/neg wires on the new ones exactly like the old filters were wired! :eek::eek:

This is one hobby were you make your own luck, so i say make it good, Be careful and do not get in a hurry. Recheck everything you did before plugging it in. John
Download a service manual.
 
Great advice John, especially the "drink good beer" item!! I would only add to ask questions (with clear pictures added) when you aren't sure of something. There is decades of experience at your disposal here. Lastly, welcome to AK!
 
KutzlerTrans said:
Welcome to AK!

Read, Read, & Read. Lots to tell you, but i will just say the basic stuff, Like

Build a simple Dim Bulb Tester
Do one board at a time and Test the unit each time.
write down everything on paper before unsoldering, Like,
cap direction and value
Wire colors, if you are removing wires
Unsolder the whole pin, if removing wires.
Use cloth over the socket used to remove the face plate.
Use a thick pad on your work bench to protect the receiver from getting scratched.
Use a variable temp solder station. 400 degrees works well for me.
Use good solder. Kester .030 thick.http://www.amazon.com/Kester-Rosin-Core-Solder-Spool/dp/B00068IJPO

Take before and after pictures.
Use good heatsink paste. No silver stuff.
CleaN your work with 100% rubbing alcohol, and drink good beer, not the cheap stuff.
don't get 100uf mixed up with 100v. :D
Unplug it before you work on it and adjust everything to spec,(p/s voltage dc offset idle current) according to your service manual. do not use dbt when adjusting voltages.

Upping your filters to the numbers you mentioned is fine. Just make damn sure you put the pos/neg wires on the new ones exactly like the old filters were wired! :eek::eek:

This is one hobby were you make your own luck, so i say make it good, Be careful and do not get in a hurry. Recheck everything you did before plugging it in. John
Download a service manual.
Click to expand...

All great advice and many of your suggestions I learnt doing my 2200B. Especially the pictures and doing one board at at time and yes lots of reading. I didn't do the Dim bulb tester, but will, since I have all the materials to make it already (left over from finishing the basement) just need the faceplate sweet! oh and the cloth around the socket for the faceplate bolts, simple but genius, I should have thought of that myself. I was really careful though, removing them with a wrench as I have seen many, as you have, all scratched up around the bolts, really looks terrible. Crazy to go through the work to refurbish them if it doesn't look good also. Cowdogs unit looks brand new cool!!! Not really planning to do a bunch of these but maybe a few to pass on to the next Gen to enjoy (oh and myself in the meantime).

A follow up question or 2 if I could.

Cowdog used the larger 8200mf instead of the 8600mf that was in it originally. I see your comment about upping the filter numbers, I take that as, it won't mess anything up??? One thing I liked about it is that they fit back into the original hold downs giving it a more original look than some of the modifications I've seen people use to mount the new smaller matching ones.

2nd can I change the Caps on the tuner boards without having to take it in to a shop for re-alignment. The outfit I bought my (Capacitor Kit) from said not to do the Tuner boards unless I have an O-scope and signal generator. Not sure why, seems like if your just replacing with the same mf nothing would change. Can you advise.

Also what do you mean by "do not use dbt when adjusting voltages" ? What is dbt?

Thanks for the encouragement.
Blessings
 
rBuckner said:
Great advice John, especially the "drink good beer" item!! I would only add to ask questions (with clear pictures added) when you aren't sure of something. There is decades of experience at your disposal here. Lastly, welcome to AK!
Click to expand...
rbukner
Thanks for the welcome and if your offering advise, I won't hesitate to take your advice and ask questions. I'm the same way, if I can help someone else with what I know, I'm glad to do it.
Peace
 
I personally would stay away from doing the fm boards, I have created problems in that area and it is not really a hot spot to worry about. You are correct in saying the replacements would be the same as factory and there should not be a change for the worse by recapping FM, but one simple mistake could cause no fm or stereo. Its your receiver and you are more than welcome to do them if you wish. All them parts grew old together and its best to not kick a sleeping dog. I got kicked in the butt by one after recapping it, so that is all i can tell you.

DBT dim bulb tester. It is like having a fuse that lights up, instead of blowing. The light bulb becomes the load instead of your receiver, in the event of a short. The excess current available during a short in the receiver lights the filament. Google it.

Filter capacitors. during the rectifying process, the filter capacitors store voltage and release it to jump the gap as the voltage starts to drop(ripple). Too little of a value will not store enough to fill the gap and too big will be a capacitor that never quite discharges fast enough. and create diminishing returns. I am not sure, but it may have to do with phase issues if it gets too big.
So how big can you go???. i would say 20% is safe, but i have read more,
. The voltage can be higher. But no value should be less than original specs. Others more intelligent than me can add to this.

This should not be done to a frequency filtering circuit .
c11.jpg

, high pass, low pass
 
KutzlerTrans said:
I personally would stay away from doing the fm boards, I have created problems in that area and it is not really a hot spot to worry about. You are correct in saying the replacements would be the same as factory and there should not be a change for the worse by recapping FM, but one simple mistake could cause no fm or stereo. Its your receiver and you are more than welcome to do them if you wish. All them parts grew old together and its best to not kick a sleeping dog. I got kicked in the butt by one after recapping it, so that is all i can tell you.

DBT dim bulb tester. It is like having a fuse that lights up, instead of blowing. The light bulb becomes the load instead of your receiver, in the event of a short. The excess current available during a short in the receiver lights the filament. Google it.

Filter capacitors. during the rectifying process, the filter capacitors store voltage and release it to jump the gap as the voltage starts to drop(ripple). Too little of a value will not store enough to fill the gap and too big will be a capacitor that never quite discharges fast enough. and create diminishing returns. I am not sure, but it may have to do with phase issues if it gets too big.
So how big can you go???. i would say 20% is safe, but i have read more,
. The voltage can be higher. But no value should be less than original specs. Others more intelligent than me can add to this.

This should not be done to a frequency filtering circuit .
c11.jpg

, high pass, low pass
Click to expand...
I think I will take your advice about leaving the the FM boards alone. Unless I ever come across one of those $25.00 thrift shop finds or find one sticking out of someones trash can on the way home from church (that was the best one I read) someone was living right. Hey if its free why not.

The DBT abbreviation totally went by me, I get it. Don't adjust the voltages with it plugged in.

I'm not sure what to do with the Filter caps. I really like that the larger ones don't need modified, but also want it to sound good and last. I think I will read some more. Maybe Cowdog can chime in on how his is doing with the larger ones so far.

Quick question though about the 2220B that I refurbished/re-capped. The DC offset and Bias settings would not stay constant. Granted the fluctuation is small, in the .1 mV range (example) the DC offset reading would start at 0 but go up to .2 or .4 or down to -.2 to -.4 , never fluctuating as much as a whole volt, but was thinking it should stay constant. Is that normal or is there something else that needs replaced? transistors, etc.
 
I am not a fan of raising main filter caps by very much but going from 6800 to 8200 isn't real bad. The issue is that the higher the capacitance, the higher the surger current at turn on. That current surges through the rectifier diodes, stressing them. That can lead to earlier failure. One can always change those (which may be a single part called a bridge) to make the modification safe. As John mentions, there's a point where the additional capacitance doesn't help any more.

On the tuner boards, changing the caps doesn't require an alignment. The danger as John points out is the subtle short or not quite soldered lead that causes a failure. These circuits require some knowledge to troubleshoot and an oscilloscope.

The bias voltage never sits still and the fluctuations you see, if you mean -0.4mV to +0.4mV, are great! If you mean -0.4V to 0.4V, that would be bad and likely your woofer would be pumping in and out!! That is unless you had the volume knob up and had source material running on whatever input was selected.
 
Temperature will fluctuate the readings as it warms up. Did you put new thermo paste on all the transistors with heat sinks?. Dirty adjuster pots?
 
rBuckner said:
I am not a fan of raising main filter caps by very much but going from 6800 to 8200 isn't real bad. The issue is that the higher the capacitance, the higher the surger current at turn on. That current surges through the rectifier diodes, stressing them. That can lead to earlier failure. One can always change those (which may be a single part called a bridge) to make the modification safe. As John mentions, there's a point where the additional capacitance doesn't help any more.

On the tuner boards, changing the caps doesn't require an alignment. The danger as John points out is the subtle short or not quite soldered lead that causes a failure. These circuits require some knowledge to troubleshoot and an oscilloscope.

The bias voltage never sits still and the fluctuations you see, if you mean -0.4mV to +0.4mV, are great! If you mean -0.4V to 0.4V, that would be bad and likely your woofer would be pumping in and out!! That is unless you had the volume knob up and had source material running on whatever input was selected.
Click to expand...
I get your point about not raising the filter caps by much, I don't really want too, just thought it was cool that they fit back in so nice. Have you tried it before?

Also get your and Johns point about the tuner board that stuff is really close together. I'm putting that on the back burner for now.

As far as the voltage your first example is correct, fluctuates from around -0.4mV to +0.4mV and no movement on the woofers. When setting the Offset, I had the selector on Tape, no speakers hooked up and the volume all the way down. I see Johns comment about it warming up. I read that somewhere and did have it warmed up. Maybe it's normal, just thought I would ask.

I will say that I've been using the 2220B now for about a week and it sounds really good. I read in a few places that there is a break in period after re-capping. I'm not sure if that's true, but the night before last while starting on the 2230B I was listening to the 2220B and could swear that it sounded better, the Bass seemed stronger and generally a tighter sound. Could be my imagination but don't think so because I wasn't really focusing on it.
 
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