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Early MXR Phase 90 pics (Data Dump)

Posted: Sun Oct 25, 2020 9:15 pm
by fernieite
Hey guys. I just took a bunch of photos of my old 1973/74 workhorse Phase 90. I've had this thing for a long time. Hope you dig them. :tu:

The pot is dated 137 7346, so the 46th week of 1973. This seems to be a very common pot date for early MXR pedals. They must have bought a ton of them.

The chips are dated the 39th week of 1973.

I replaced the old deteriorated foam, but you can see lots of particles left over on the board. The only thing changed is the battery connector, I think. Oh yeah, and the screws look too new, so are probably replacements...


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Re: Early MXR Phase 90 pics

Posted: Sun Oct 25, 2020 9:16 pm
by fernieite
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Re: Early MXR Phase 90 pics

Posted: Mon Oct 26, 2020 12:19 am
by jreeves47
super awesome! I've only seen a couple earlier than yours. how's it sound?
can you read the revision number on the track side of the circuit board? its P90 followed by a lower case letter

Re: Early MXR Phase 90 pics

Posted: Mon Oct 26, 2020 1:14 am
by fernieite
Cool. It sounds awesome, I love it!

The circuit revision is P90c.

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Here's another one of the pot. It's not stamped Mxr like some of them are.

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Re: Early MXR Phase 90 pics (Data Dump)

Posted: Mon Oct 26, 2020 2:41 am
by jreeves47
thanks!
here's the earliest pic I've seen of one - serial number 1040 so might be the 40th one made

Re: Early MXR Phase 90 pics (Data Dump)

Posted: Mon Oct 26, 2020 3:58 am
by fernieite
Man, the layout is quite different from my revision c. :smashed:

Is that the first circuit layout? - P90 or P90b? Anymore photos? :badlove: