Bypass capacitor for an M7551 board

[leegleason]

I have an M7551 memory card that has a bad chip on it. The bypass cap next to it is alsp a casualty, got melted during desoldering the chip (my first time using a Hakko FR-301 - great tool, but it was a little wider than I thought and touched the cap). The markings on the cap ar R5E, 474Z, 433 I'm guessing it's a .47mf cap, Z grade tolerance, but I'm wondering what the R5E and the 433 refer to. I'm also guessing, I could get away with not replacing it, but, might as well. Any ideas? And any suggestions as to which of the several cap technologies to use to replace it with?

 

[daver2]

Aren't the schematics and Bill of Materials available for this card?

Dave

 

[leegleason]

Aren't the schematics and Bill of Materials available for this card?

Dave

The Gunkies page on this board says that none are known to be online.

 

[Chuck(G)]

I'm with you on the .47 µF cap. 433 doesn't sound like a standard value designator.

 

[shirsch]

The Gunkies page on this board says that none are known to be online.

Sometimes one can find DEC information in non-obvious documentation. Worth a bit of poking around through drawing sets, maybe.

 

[Bitly]

The MSV11-R schematics are part of the 11/84 print set (MP-02015), and they list two xx47xx capacitor options:
0.47uF 25V Ceramic (20%) and 0.047uF 50V Ceramic (+80%/-20%).

CW

 

[leegleason]

The MSV11-R schematics are part of the 11/84 print set (MP-02015), and they list two xx47xx capacitor options:
0.47uF 25V Ceramic (20%) and 0.047uF 50V Ceramic (+80%/-20%).

CW

Thanks!

 

[leegleason]

OK, got the new chips (bought 5 of 'em, in case finding the right one to change turned out to be a game of desoldering whack-a-mole). I'm waiting for the bypass cap to come from Mouser, so I figured, I'd give it a try without a cap in that spot. Got the right bad chip on the first try. Worked fine, passes the diags, without the cap. It's just a hobby system, so I'll run it without until the new cap gets here.