Marantz 2325: what do VD1221M diodes look like?

rlisin

Quad 4 life
I have just bought and received a Marantz 2325, poor cosmetics (needs a new faceplate, bolts and 1 button, which Im'm getting next week, hopefully). But it works perfectly. I adjusted DC offset and bias without any problems (if you don't count a bit confusing marking of the test pin J708), but there's one problem.

I read in a few threads that VD1221M diodes H718 and H719 should be replaced with 1S1555a or 1N4148 for safety reasons, but later in the production Marantz installed 1S1555a (that do not need to be replaced). My 2325 is from Feb. 1977, not sure if that qualifies as "later production). And the problem is I could not find any pics of a VD1221M diode online. I did find pics of VD1221 (without "M"), which looks like a black blob on a wire, am I correct to assume that VD1221M looks like that too?

What I have in my 2325 is this:

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It looks like a 1S1555a diode and I assume it is, but would be grateful if someone who knows (and not guesses like I do) could confirm.

Here's a few more pics of my 2325

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And apparently its new owner:

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My understanding is the 2325 diode service mod instructed to replace the early production amp boards VD1221M diodes with glass diodes such as 1N4148s. The VD1221Ms are not glass cylinders but are small round usually black components as in my photo below. Your photo shows a glass diode in the H718 position so you are all set, no fix needed (confirm H719 also has the glass diode and both boards are same). Photo of glass diode below as well for comparison. Good luck with your project!

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Thanks for the confirmation! Took me a while to locate H719 (not very visible without removing the amp board and I didn't want to do that), but it is the same as H718, and both boards have these glass diodes. That's one less thing to worry about then.

I will post pics once i get the cosmetics sorted out.
 
I did a rebuild on my 2325 and it is everything I hoped it would be. It's my daily driver, and pumps out my classic rock effortlessly. If you think you would ever consider a black replacement faceplate, check with Bob Speece (AK member wlhd1610) In the past, he has had some beautiful laser etched black faceplates for the 2325.
 
I'm in Europe, so I rely on European sources for parts, it's faster and cheaper this way. I bought a used silver faceplate in a good shape. There's a place in Berlin that makes black faceplate relipcas for Marantz receivers, but it would be 3 times more expensive and I prefer silver anyway.

Not sure if the Marantz will become my daily driver, as good as it is (and I do love what I'm hearing), I'm running a Citation 16 power amp with a HK 725 pre and it's not easy to beat that combo. But I'm really happy to add it to my "fleet". Always wanted a "monster" Marantz, the most powerful one I had until now was a 4400, but I never run it in quad mode, so it's only 50 WPC. I couldn't run it in bridged stereo mode anyway, most of my speakers are 4 ohm.
 
In the meantime I corrected the lights. Turned out that 3 out of 6 dial lamps were 12V instead of 8V, and miniature 3mm green bulbs were sitting behind the meters. I replaced them with correct lamps, looks much better now.

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