Saturday, December 20, 2014

Marantz 2252B Receiver

Marantz 2252B Receiver

It would seemed that I've been getting a lot of 50 class 22XX receivers lately. The difference between the 2250B/52 and B variants is all substantial in PCB design and layout. 

Power Supply
This is an interesting design. The power supply and power amplifier board and relay are all located on a single PCB section. Typically I do not like this. IIt creates a significant chance of noise and extra heat dissipation issues. 

On the power supply I used Panasonic FC and FRs, a long life high temp capacitor. Two diodes, a common cathode and common anode should be replace here with a more reliable modern MUR1620CTG/CTRG diodes in the same package (TO-220)
 The relay is another 4 contact Omron MY-4-02 type. What makes this one easier than say the 2330 MY4 is at almost an exact drop in replacement pin wise. 

Power Amplifier 
All the caps were replaced with Elna Silmic II's and Nichicon FG capacitors. One thing to mind is C701, the polarity is backwards on the decoupling cap in this stage.
Access is hard here. Your best bet is to remove the filter capacitors mounted under the chassis (same with the 1070 integrated) and remove the speaker switch arms. I think this was a design issue of fabrication VS repair. The large filter caps were replaced with two 6800uf 80V Nichicon KG type, again these are mounted under the amp boards. New mica insulators and thermal compound was applied as well.

This is a fairly easy access board by pulling the pots away from the chassis and pulling out. I used Nichicon MUSE BP capacitors at CE23/24 as theirs no significant DC here, ECW PP's would be nice here too. The two small brown films which I don't like (big browns are stay) were replaced with two .22uf ECW PP Panasonic films. The rest were replaced with WIMA MKS2 and Elna Silmic II capacitors.

This is another interesting layout. The phono is combined with the tone control and meter switching. The switching function is pulled through a elongated shaft from the faceplate. The meter capacitor and switching is here also.  WIMA MKS2 (small stage) and Elna Silmic II and Nichicon FG capacitors were used here.

Added a new EG1018-ND power switch and safety capacitor,note the extension shaft. And thats a wrap.

One thing to note on the 2252B is a signal meter issue. After talking with several folks it would appear this is consistent as well where the signal meter dances in all functions. I think this is due to the capacitor way back the line VS across the actual meter, at some point I would advise to place a jumper at C422 and pull the cap across the meter, this may cure that.

Overall its a very nice sounding unit once recapped, very robust and very attractive faceplate, getting away from the black and black bevel and going to the silver dial plate.

Tuesday, December 9, 2014

Another 1060 arrived last week, thought I'd show some variations on the 1060 I did before. Last month I posted a more in depth walk through of the 1060 Integrated restoration, if you need additional information or schematics; go to that post.

Fairly similar to the other, Power Supply was replaced with Panasonic FR capacitors and two UF4005 diodes replaced. 

On the Amplifier board I went with Silmic II's, FG's and WIMA's. This time I also dropped in a GEN II matched up .1uf's PP capacitors replacing the original thin brown films at 725/726. I used the Gen II in the same stage in the Marantz 2325 I restored.  I was pretty impressed with the results, as I am again this time. The Main caps were replaced with a Nichicon KG 10000uf and the couplings with THA 6800ufs.

The Pre-Amp board is pretty much the same, I used WIMA's and Silmic II's along with MUSE for the bipolar replacements.  The green films at 401/402 were replaced with matched .22uf Mudorf EVO PP's. The same as the 2230 pre amplifier, IMHO these are excellent for smoothing out details that are too sharp, in fact if your gonna be using the Sonicaps at all, I would recommend these, as the sonicaps by themselves can be a lil bright. 

The Phono's tantalums were replaced WIMA and FG and Silmic II's used throughout. H905/906 were replaced with matched KSC1845 BJT's.

I should add that this particular 1060 is just pristine! I love working on these conditions, the chassis still has a sparkle to it. I also wanted too add a note on the faceplate. The owner decided to go with one of Tony's (TMZ) black faceplate. The finish, and constructed is exactly what I anticipated from his other plates…TOTL :)

Monday, December 8, 2014

Marantz 2220 Receiver (NonB)

Marantz 2220
Just got this 2220 in here a few days ago for a basic restore for a fellow. Just covering the phono/PS tone and amplifier boards and main caps, switch etc… Right next to the 2220B and 1060, the 2220 has got to be one of the easiest units to work on, the chassis is very open and accessible. The 2220 is an interesting unit, a pretty common PS noted on several of the lower watt 22XX units with no regulator adjustment. Also these models don't have the bi-pin functions. About the only qualm I have with this unit is its not properly shielding inside, otherwise their really great sounding lower watt receivers, with really clean simple plates.

Power Supply
All the caps were replaced with low ESR/high tempt Panasonic FR's which seem to be perfect for the PS. Three S1B-01-02 diodes at H804/805/808 were replaced with a single UF4005 diode. I've still got to scrape off some excess dried glue from the original caps along with some oozed flux on some PCB's, back then everything was so bulky, I thought about a larger diameter cap but I wasn't happy with specs VS size aesthetics in this case.

The tone board topography is very similar to the 2230 I noticed, I decided to keep the films present, the fat browns are hard to beat. Elna Silmic II's were used throughout and WIMA MKS2 were placed in the bi-polar section 701/702. This boards has a bunch 458's that the ksc1845's are a go to for. If one removes the tone control PCB the tone board pulls out completely almost and can be contorted easily for more access. 

The axial here was replaced with the Nichicon TVX I like to use along with Elna Silmic II's and a KG. No diodes to update on this board but H905/906 845's were replaced with matched KSC1845's. The films again were the fat browns. I suppose if I were to replace them the only vie found to come close is the ECW PP panasonic films. Ive used them to replace the yuck original gray films. 

I've never really been a fan of the symmetrical single PCB design when it comes to the amplifier board but alas. Access is fairly easy to pull the board from the unit with a few common grounds to mind. The other trick to this unit was the transistors. This model did not use transistor sockets for the TO-3 type, they used insulated hardware and soldered the leads…Talk about a PITA, if I come across a 2220 again it will most definitely be ordering sockets for it, if they can fit. 
The bypass or 701/702 were replaced with small MKS2 .47ufs and Elna Silmic II's used throughout the amplifier board. New Mica and compound and well.

One thing I did like is the filter/coupling selection, I hate the amp boards smack next to these caps because of the radiant heat put off by the boards. So I kept my normal selection of a Panasonic THA (I think IMHO this is the best cap for this location, sonically better than the KG Ive tried) at the filter and Nichicon KG's but went with 35mm/35mm caps to create a low profile to try and open up some air volume between the caps and board. Im incredibly happy with how this turned out with the symmetric PCB layout 

I did find a 10amp heavy duty automotive power switch inside originally that was replaced with a EG1018-ND dpdt switch and a new TDK X1Y2 safety cap. Threw in some new vellum and LED few lamps for the dial and meter. I did have to reflow the Stereo indicator, Ive had to do this is about a half dozen 22XX's now, either when folks either replace them or heat related solder wear im not sure.

Wednesday, December 3, 2014

Marantz Model 22 Receiver

Marantz Model 22

Heres a  fun one, a Marantz Model 22, back when Marantz started going over seas to Japan, we see some of the  techniques used here on the 22XXs a lil later on.

P800 Power Supply
The 1000uf capacitors have a common ground/case not typically in later variants, the trick is getting the right lead spacing here. The particular power supply is rather interesting, consisting of a dual power supply, on half is dedicated to the AM/FM stages and the rest for amplifier phone/pre sections. P600 and P700 PCB's.
Lytics here were replaced with Panasonic FR and FC's. 

A new EG1018-ND switch with a vishay X1Y2 safety capacitor was installed.  The large can caps were replaced with my favorite low profile 4700uf Panasonic THA's. 

P400 Tone
Silmics and Nichicons were used extensively on this board, transistors at H401/402 were replaced with matched hfe KSC1845's. 

P300 Phono
This is a pretty familiar design I've, the lyrics here were replaced with Silmics and Nichicons

P600/700 DC FM/AM Amplifier
The latter half at P600 is used for the amplifier board on this model through the dual PS. Just a few lyrics here to replace with Nichicons, I also replaced the large films with Panasonic ECW PP type. The Bias can be obtained across either emitter resistors R651-654, adjustments are bad off the board back behind the transistor TO-3 bank, the pots center stage are Offset adjustments. New Mica insulators and thermal compound was applied.  P700 was recapped with Nichicons and Silmics along with H705/706 (2SC732) replaced with  matched KSC1845's.

I also recapped the speaker relay PCB at P980 with Nichicons while we have access and are addressing the PS and such.

Heres a listed of noted service bulletins -C807
-R617/618 9.1K 1/2 RESISTOR (WAS 10K) 
470uf to 330uf @ c804
H801/802 Transistor Upgrade (done prior on most units)