2270 Phono

[sssboa]

Strangely this is from a 2270 with higher serial number (59000) than my first one (55000) but seems to have older parts.
Diodes H707 and H708 should be 1S1212 but look like the notorious VD1212 only of different colour - red and green instead of red and white (they looked like typical diodes in the other 2270, should I replace them and with what?). H705-706 are 2SC458, I had different transistors here in the older one. One ceramic looks burnt (C712), what do you think? Some where replaced by small electrolytics in serial (C701, C702). Does anyone remember if C703 and C704 22uF are originally aluminum electrolytic or tantalum? In service manual both tantalum and aluminum electrolytic are described the same as electrolytic.

 

[catrafter]

From my experience with other Marantz models that have commonality with the 2230, 2270 and from what I have learned from other knowledgeable techs both here on AK and in the field, I perform the following updates.
Replace the 2SC458 transistors (H705 and H706) on the Phono preamp board with 2SC2240BL or KSC1845 types. Follow the silk screen as to their orientation. The originals fail noisy with age.
If H709 looks like an epoxy bead, replace it with 2 1N4448 diodes in series.
If H707 and 708 look the same as H709 replace them with ONE 1N4448 each.
I like to replace C713 with a 220uF/50V Panasonic EEU-FC1H221 part to improve local filtering, watch the polarity on this, some boards are marked wrong.
If the input and output coupling caps (C701, C702) are electrolytic types, replace them with 1uF/250V film types, Panasonic ECQ-E2105KF.
If they and the output coupling caps are .47uF, you might gain a few Hz on the bottom end if you change them to 1uF/250V types like the later models have.
The 2230 and 2270 Phono preamp has a reference designator of P700. Most other models designate it as P400, but the same updates apply.

Tom

 

[sssboa]

From my experience with other Marantz models that have commonality with the 2230, 2270 and from what I have learned from other knowledgeable techs both here on AK and in the field, I perform the following updates.
Replace the 2SC458 transistors (H705 and H706) on the Phono preamp board with 2SC2240BL or KSC1845 types. Follow the silk screen as to their orientation. The originals fail noisy with age.
If H709 looks like an epoxy bead, replace it with 2 1N4448 diodes in series.
If H707 and 708 look the same as H709 replace them with ONE 1N4448 each.
I like to replace C713 with a 220uF/50V Panasonic EEU-FC1H221 part to improve local filtering, watch the polarity on this, some boards are marked wrong.
If the input and output coupling caps (C701, C702) are electrolytic types, replace them with 1uF/250V film types, Panasonic ECQ-E2105KF.
If they and the output coupling caps are .47uF, you might gain a few Hz on the bottom end if you change them to 1uF/250V types like the later models have.
The 2230 and 2270 Phono preamp has a reference designator of P700. Most other models designate it as P400, but the same updates apply.

Tom

OK. So should I replace both pairs of 0.47uF caps? The first one (C701, C702) on the left in my picture has already been replaced by someone with electrolytic caps in series, the other pair you can see on the right, the 2 big brown Mylars C714 and C715.

 

[catrafter]

I would replace C701 and C702 for sure. C714 and C715 are optional. Bumping the value from 0.47µF to 1µF (like the later models) might help the bottom end just a bit.

Tom

 

[sssboa]

I just checked 2275, it has 2x 1uF on both sides of the board + 2x 47uF instead of 2x 22uF.
Shouldn't all these be swapped for consistency and does 2275 really sound more bassy on phono output than stock 2270?

 

[sssboa]

From my experience with other Marantz models that have commonality with the 2230, 2270 and from what I have learned from other knowledgeable techs both here on AK and in the field, I perform the following updates.
Replace the 2SC458 transistors (H705 and H706) on the Phono preamp board with 2SC2240BL or KSC1845 types. Follow the silk screen as to their orientation. The originals fail noisy with age.
If H709 looks like an epoxy bead, replace it with 2 1N4448 diodes in series.
If H707 and 708 look the same as H709 replace them with ONE 1N4448 each.
I like to replace C713 with a 220uF/50V Panasonic EEU-FC1H221 part to improve local filtering, watch the polarity on this, some boards are marked wrong.
If the input and output coupling caps (C701, C702) are electrolytic types, replace them with 1uF/250V film types, Panasonic ECQ-E2105KF.
If they and the output coupling caps are .47uF, you might gain a few Hz on the bottom end if you change them to 1uF/250V types like the later models have.
The 2230 and 2270 Phono preamp has a reference designator of P700. Most other models designate it as P400, but the same updates apply.

Tom

1N4448 or 1N4148?
OK, just read it doesn't matter.

 

[sssboa]

Could someone confirm the voltage rating of the two 22uF caps as seen on the original board set-up not in service manual. Service manual states 22uF@6.3V, I'm afraid it may be a mistake.

 

[catrafter]

I just checked 2275, it has 2x 1uF on both sides of the board + 2x 47uF instead of 2x 22uF.
Shouldn't all these be swapped for consistency and does 2275 really sound more bassy on phono output than stock 2270?

Some use 22µF, some use 47µF. It doesn't seem to affect the frequency response much.

Could someone confirm the voltage rating of the two 22uF caps as seen on the original board set-up not in service manual. Service manual states 22uF@6.3V, I'm afraid it may be a mistake.

There should be very little DC voltage on these caps so 6.3V are probably fine. I think they used whatever was on hand, I have seen 16 and 25V in those locations as well. There has been some discussion about lower voltage electrolytics having lower dielectric absorption than higher voltage ones.

Tom

 

[sssboa]

Some use 22µF, some use 47µF. It doesn't seem to affect the frequency response much.



There should be very little DC voltage on these caps so 6.3V are probably fine. I think they used whatever was on hand, I have seen 16 and 25V in those locations as well. There has been some discussion about lower voltage electrolytics having lower dielectric absorption than higher voltage ones.

Tom

Are they tantalum originally? I have already electrolytic replacements in my current one.
Just managed to find a pic. They were tantalum with yellow tops. I will change them to today's tantalum cause I'm orthodox.

 

[thxdave]

Shalom