2275 Has Arrived! Recap Underway!

[MarkyM]

I noticed that you used mostly Nichicon KA/KT 105 degree.
Any reason not to choose Silmic II?
I think you have done a lot of research before you bought...

Also which ones are WIMA caps on the list? - all Film caps from the list?
I saw many WIMA caps from your photos.

Thanks!

I wanted to use all 105 degree caps for long term stability. The Nichicon KT/KA are the only "audio" rated 105 degree caps as far as I could find.

After reading through most of the 54 pages of the "capacitor shootout" thread I saw no mention of the Nichicon KA and KT as it seems they did not come out until 2012 (the thread originated in 2011). So using a link from Page 44 of that thread, this quote from patfont was good enough for me:

Originally Posted by patfont: Hate to spoil the party early but this is not Nichicon's best sounding audio cap, and you know what else that means. Anyway for those who must use a 105C and 2000 hour cap this will be a fine choice, as it is "Designed for Audio," and not just a "General Purpose" capacitor. And I think Nichicon knows what they are doing!

I think Nichicon knows what they are doing too!

I did not end up using any Wimas. I bought a pair but they arrived late so I went with a pair of Nichicon ES bipolar I had on hand instead.

For all the smaller value coupling caps I used stacked metallized polyester film caps which should be better than any electrolytic.

The receiver sounds great!!!

 

[Pauljuhn]

The receiver sounds great!!!

That's the most important thing to me as well.

Currently, My 2275 sounds very sweet.
Sometimes FM signal strength starts low and then getting better.
Sometimes FM tuning meter moves a bit from middle position after listening a while.
Is this normal?

I am going to do LED upgrade first then Re-Cap one by one....
Thanks for the photos and Caps list again...

 

[MarkyM]

That's the most important thing to me as well.

Currently, My 2275 sounds very sweet.
Sometimes FM signal strength starts low and then getting better.

Sometimes FM tuning meter moves a bit from middle position after listening a while.

Is this normal?

I am going to do LED upgrade first then Re-Cap one by one....
Thanks for the photos and Caps list again...

Slowly increasing signal strength is not normal.

If it is just a small amount, some initial drift is normal for the center-tune meter.

You're welcome.

 

[c.coyle]

. . . .

Sometimes FM signal strength starts low and then getting better.

Over how much time? Minutes? Hours? Indoor antenna? Is something or someone moving close to the antenna? Possibly a failing component in the RF section or somewhere else.

Sometimes FM tuning meter moves a bit from middle position after listening a while.

Could be an alignment issue. Could be a component in a tuned circuit going off value as it heats up.

 

[Pauljuhn]

Change my question

Over how much time? Minutes? Hours? Indoor antenna? Is something or someone moving close to the antenna? Possibly a failing component in the RF section or somewhere else.



Could be an alignment issue. Could be a component in a tuned circuit going off value as it heats up.

I have to re-phrase my question for better answer.
From same FM station, same antenna, same surroundings, is it normal to have different signal strength?
From the scale of 0 to 5, Sometimes I get 1, sometimes I get 4+.

 

[Bunty2]

I have to re-phrase my question for better answer.
From same FM station, same antenna, same surroundings, is it normal to have different signal strength?
From the scale of 0 to 5, Sometimes I get 1, sometimes I get 4+.

It should stay close to one signal strength if a local or semi-local. However, malfunctions at the station's transmitter may result in changing signal strengths, but stations usually get transmitter trouble fixed soon.

 

[rBuckner]

@ Paul: I wonder if your +13 power supply is wafting about. I'd say to check that first to see if it's changing as the signal strength changes.

 

[Pauljuhn]

@ Paul: I wonder if your +13 power supply is wafting about. I'd say to check that first to see if it's changing as the signal strength changes.

Please tell me more about +13 power supply.
I have no idea about it.
I checked the power it is 35V.

 

[rBuckner]

It is what powers the FM circuitry along with some other things. It is output from the P800 power supply board at pin J806. It has a voltage of +13.4Vdc as listed on the service manual page 49. It is set by 14 volt zener diode H810 (which itself filtered by cap C806). Those two would be my main suspects IF the voltage at J806 is off.

 

[Pauljuhn]

Check J806

It is what powers the FM circuitry along with some other things. It is output from the P800 power supply board at pin J806. It has a voltage of +13.4Vdc as listed on the service manual page 49. It is set by 14 volt zener diode H810 (which itself filtered by cap C806). Those two would be my main suspects IF the voltage at J806 is off.

I think it is page 39 not 49?.(There are pages only up to 39 in my pdf)
I found J806 but how do I measure the voltage from it?
One from J806 and the other should go?

 

[rBuckner]

True, there are several PDFs out there!

You would put the plus/red probe on the pin and the negative/black to chassis ground anywhere convenient and safe from slippage to something dangerous like line voltage or amp output transistors, etc. Some clip leads would be best as you're going to be observing the reading until the FM meter changes.

 

[Bunty2]

I posted this back earlier in the thread, it's kind of hard to see, the white wires go to the negative and the red leads go to the positive leads of the cap pair and attach to the cap with ring terminals.

Here's a better picture, this is of a 2325.

Tom

I recently did a partial recap job on my Marantz 2275. It included replacing the filter caps. Didn't add bypass caps. I've read conflicting opinions about the need to use them on today's modern filter caps. But surely hearing is believing. So have most people heard an audible difference for the better when adding bypass caps?

 

[MarkyM]

Bypass Caps

IMHO, bypass caps should be located (and will do much more good) at the circuitry being used by that power rail, rather than at the main filter caps.

This will ensure that any noise etc. picked up by the wiring will be bypassed right where it enters the board / chip etc.

If properly designed as above, there should be no difference in sound whether there are bypass caps at the main filter caps or not.

 

[Pauljuhn]

J803

True, there are several PDFs out there!

You would put the plus/red probe on the pin and the negative/black to chassis ground anywhere convenient and safe from slippage to something dangerous like line voltage or amp output transistors, etc. Some clip leads would be best as you're going to be observing the reading until the FM meter changes.

I managed to find the voltage fluctuate.
It shows as low as 7.2v but it becomes 13.25v when signal strength is highest.
What needs to be done?
But most of the time, the strength is good, only sometimes it is low.
It is J806 (not J803 - mistake in heading)

 

[rBuckner]

Aha! We know the reason now. First it would be good to know the raw source voltage of about +32vdc is stable at the power transistor H804's collector which is the tab. In any case, check that the solder joints are good at the power transistor (H804). This transistor could be faulty on it's own of course.

If the +32v is stable then I'd say to replace: H810 and C806 and possibly R808 but I doubt it. Again also H804.

If the +32 is bad then the possible bad guys are:
Source: rectifier H808 and cap C801
32v dropping/filter: R807 and C805
Output transistor: H804.

Ask if you need part recommendations. Good luck!

 

[Pauljuhn]

Aha! We know the reason now. First it would be good to know the raw source voltage of about +32vdc is stable at the power transistor H804's collector which is the tab. In any case, check that the solder joints are good at the power transistor (H804). This transistor could be faulty on it's own of course.

If the +32v is stable then I'd say to replace: H810 and C806 and possibly R808 but I doubt it. Again also H804.

If the +32 is bad then the possible bad guys are:
Source: rectifier H808 and cap C801
32v dropping/filter: R807 and C805
Output transistor: H804.

Ask if you need part recommendations. Good luck!

As I said, most of the time signal strength is high.
I can't just wait for the time when it becomes low...
Please give me detailed instruction how to measure 32v from H804.
Also I need all part recommendations. Thanks!

 

[Pauljuhn]

LED Conversion

Thanks,

It looks more even in these photos than it really is because of the overexposure. I'll post some better photos at some point.

The LED kit was from Northridge.

I used one 560 Ohm resistor for the indicator lamp common and another for the Stereo light because it is separate. The fuse-lamp-LED's have no added resistor.

I have not replaced the vellum. It is original. This thing must have been kept in an industrial clean room for 40 years.

I think what you are seeing above the indicators in my photo is due to the overexposure, a low camera angle and the fact that the top cover is off.

I have done LED conversion:
It has some greenish tint I think - The LED's are from Northridge.
What do you think?

 

[thadius65]

Bravo! Very clean looking. I like it! Now slip on a WC22 and make her look as good as she can!

 

[Bunty2]

Bravo! Very clean looking. I like it! Now slip on a WC22 and make her look as good as she can!

But I think framing the silver and black in wood tends to distract from the beauty of the silver and black as well as the blue lighted display.

 

[Pauljuhn]

H804 voltage

Aha! We know the reason now. First it would be good to know the raw source voltage of about +32vdc is stable at the power transistor H804's collector which is the tab. In any case, check that the solder joints are good at the power transistor (H804). This transistor could be faulty on it's own of course.

If the +32v is stable then I'd say to replace: H810 and C806 and possibly R808 but I doubt it. Again also H804.

If the +32 is bad then the possible bad guys are:
Source: rectifier H808 and cap C801
32v dropping/filter: R807 and C805
Output transistor: H804.

Ask if you need part recommendations. Good luck!

Hi,
Please give me detail instruction on how to measure 32v for H804.
Is this J804 and chassis?
Thanks!