New 2245 in my arsenal

[Osibisa]

Picked up a s/n 31xx engraved from CL this morning in working condition. Outside is clean but needs a bath and TLC inside. Tuning string is still tight and a flick of the thumb with send the pointer almost halfway up/down the dial. Noticed that the tuning meter stays to the left of center no matter what. Doesn't hit center at all.

Two of the feet are broken off, controls slightly gummy, but otherwise in pretty good shape...

Atop my current daily driver...

 

[Osibisa]

Screwed up the formatting, so here's a few more pics ...







Haven't traced those two small caps mounted next to the main filters yet, anyone know what they are for?

Watching MBuras's work in progress for pointers.

 

[Steven Tate]

They are definitely not on the higher S/N units, but the chassis mounting holes are. I’m sure some of the experienced guys know. I will be anxious to hear what they have to say.

 

[tonebells]

I had one like that in a 1030. It was in parallel with the main power supply cap.

Tony

 

[Osibisa]

Those two 1000uf caps are actually mounted on a little platform over the extra hole in the chassis with the attaching wires running through it.
If they are wired in parallel as Tonebells suggests, that would bring the total filter capacitance up to 7800uf right? I plan to vacuum it out tomorrow as it's too dusty to mess with it now.

 

[Steven Tate]

Those two 1000uf caps are actually mounted on a little platform over the extra hole in the chassis with the attaching wires running through it.
If they are wired in parallel as Tonebells suggests, that would bring the total filter capacitance up to 7800uf right? I plan to vacuum it out tomorrow as it's too dusty to mess with it now.

That kind of makes sense. The schematic for the Pre 3900 units shows 6800 uF filter caps. The post 3900 shows a 9000 uF. I’ll bet they realized early on that they needed greater capacitance and added these on as a stopgap until they got the whole post 3900 design implemented.

 

[Fairlane]

Just recently picked up a 2245 and love it. Sound on this model is really nice.

Have you had a chance to listen to it much yet?

 

[Osibisa]

Did a vacuum, compressed air, and Deoxit on volume/balance pots this morning, giving the latter a chance to dry before powering up again.
Can confirm that the two 1000uf caps are parallel to the 6800's, fortunately none of them have vented

A couple more pics of the underside:

 

[Steven Tate]

I would replace all of those big caps with a pair of Nichicon 10000uF 63V Gold Tunes. These are common replacements in the 2245 and 2270.

 

[Osibisa]

Yes I agree .... have a pair in my 2270 and the sound is most pleasant.

Well I buttoned up the bottom cover and flipped the unit over to check PS voltage, very surprised to find that this fell out while it was upside down:



Have no idea where it might have been lodged, and suspect it might be the cause of the tuning meter issue.

Other than that, for a completely original receiver it sounds pretty good.

Not ready to dig into it yet but would like suggestions on what to check as to why the tuning meter only has movement left of center. It is centered on functions other than FM though.

 

[Fairlane]

Hopefully you "pin pointed" the issue.

Seriously though it is lucky that did not short across two points on something inside.

 

[Osibisa]

Been listening to FM all day, fixed the tuning meter issue with a minute tweek of the secondary core of L501 and now I get some deflection to the right where there was none before.
Noticed that the antenna attenuation switch was in the on position, turned it off and BAM, strong signal just about everywhere!!!
Stereo separation kicked in although the lamps have to be replaced. Very pleased with the sound so far.
Tomorrow will spin some vinyl or might hook up the RTR for Christmas music.

 

[Osibisa]

Haven't done much of anything to this receiver other than servicing the power supply & relay. It does not sound all that great in its current state.
Planned to refurb and give to my brother, but the more I looked at it the more I wanted to keep it. Guess I should not have told him just yet.

As it turns out I got my hands on another later production specimen that is in near pristine condition...




Close examination reveals that all screws still have the thread lock substance intact with three exceptions.
The left channel output transistors and one of the right channel outputs were replaced with TI SJ's ...


Interested to know how it was determined that only the SJ2514 in the right channel needed to be replaced as the 2513 is still sealed.

Observed that the amps felt a bit warm, not hot but warmer than I would have expected. Checked the idle current (0.06/both sides) and bias ... YIKES ... both sides were close to the mid 20's
Adjusted down to 5mv having to crack the paint seal on the pots. Now runs nice and cool along with idle current at 0.00.
The phono had right channel distortion with H703 - H704's collector voltage well above spec. Replaced H707, H708, & H709 with the appropriate number of 4148's and bingo, back in business!

I've taken heed to the sage advice to "resolve issues first" before performing a restoration.
Got a parts order coming in tomorrow and it's supposed to snow, so I'll have a good weekend.
The receiver sounds very good as it stands now so it's just getting a new relay, caps in the PS, main filter caps, and the rest of the phono board serviced.

Once this one is done I'll revisit the original in the thread since now I know what it is supposed to sound like!

 

[Steven Tate]

If your serial number is above 3900 and you are checking bias between J754 and J760, I believe the recommended setting is 10mV. The manual setting of 5mV at other test points is for pre 3900 serial numbers. It’s discussed a couple of places in the service manual error thread.

 

[Osibisa]

Thanks Steve, must have missed it so I'll adjust again when the other work is complete.

 

[Osibisa]

Finished work on this receiver yesterday and did not too much a difference in sound until I replaced the caps on the pre-amp board.
Prior to that bass did get a bit deeper, although remained slightly boomy. After the pre-amp work the sound tightened up and is now well defined making what I thought was a good sounding unit even better.
I used Panasonic FC series caps, but am curious if anyone may have used Elna Silmic II's instead and/or perhaps compared the two?

 

[Steven Tate]

I’ve used both and have to admit the lack of a golden ear. Both had a marked improvement over the Pre-recap sound. Like you said - tighter, better definition top and bottom. But to my ear, they sounded about the same.

 

[Osibisa]

I just got finished listening to a Rush album and while the sound was tight I had expected the bass to be projected a bit more (kind of like it was before).
The only change I made was the use of 1uf stacked film caps at C403, C404 & C414, C415 instead of the electrolytic there previously.
I'm speculating that is causing the sound change, may swap out to test my theory.

 

[Steven Tate]

I think that change to stacked films is recommended by Catrafter. It will be interesting to see if your bass comes back with the electrolytics.

 

[Osibisa]

Yes that is his recommendation, but I remember reading a thread a while ago where he made mention that the films give the cleanest signal, however if you wanted a warmer sound use 'lytic.
Where I read it or in what context I do not recall.
Figures there are no 1uf caps on hand and they are no longer available in the FC series from the top two, so when I do the low s/n unit Silmic's will be used and an a/b test can be performed.
Wonder why Marantz used two different 1uf cap voltages when both were available and size was not an issue.