Metropoulos Forum

Below are a couple of things that had me second guessing myself as I worked through the build, in no particular order:

1.) HT Fuse is a 1A sloblo; Mains fuse is 3A sloblo

2.) The unidentified hole in the chassis by the input jacks is to put a ground lug to ground the input jacks and circuit board (ground wire on the left hand side of the board to the 250uf cap) pic: http://www.putfile.com/pic/8211974

3.) I did not put a nut on the circuit board mounting hole right below the 68K resistors because the 68K resistors were in the way. pic: http://www.putfile.com/pic/8211973

4.) I had to add an extension of wire to the choke wire that goes to the filter cap board.

5.) The .1 cap on the presence pot didn't fit the same way as in my other builds. same concept, mounted differently... pic: http://www.putfile.com/pic/8211971

6.) Don't forget to mount the Buss wire on the pots to the ground lug on V5... I forgot to do this and had funky voltages during testing.. pic: http://www.putfile.com/pic/8211972

7.) I ran the ground wire from the filter cap board to the V7 ground lug... pic: http://www.putfile.com/pic/8212001 and http://www.putfile.com/pic/8211977

8.) Take note of what indicator lamp you have! The 6V lamps obviously mounts differently than a 120V... see the diagram I posted here for both options... http://forum.metroamp.com/download.php?id=5785

9.) I had to drill a hole for the HT Fuse holder in the chassis right behind the PT. pic: http://www.putfile.com/pic/8212001

10.) When testing for volts it is probably best to do so with preamp tubes in to keep the volts down across the board and reduce the risk of frying a cap...


I think these were main things that had me thinking throughout the build... did I miss anything BB?

Thanks,
Mike

gutpile wrote:2.) The unidentified hole in the chassis by the input jacks is to put a ground lug to ground the input jacks and circuit board (ground wire on the left hand side of the board to the 250uf cap) pic: http://www.putfile.com/pic/8211974

Its good for that- I used it for that myself- but Im pretty sure it was meant to be in the opposite corner. Theres no hole for the fuse holder there.

3.) I did not put a nut on the circuit board mounting hole right below the 68K resistors because the 68K resistors were in the way. pic: http://www.putfile.com/pic/8211973

Lol. I probably shouldve skipped that but I just bent it outta the way.

4.) I had to add an extension of wire to the choke wire that goes to the filter cap board.

Funny. I didnt. I had a different tranny set tho.

5.) The .1 cap on the presence pot didn't fit the same way as in my other builds. same concept, mounted differently... pic: http://www.putfile.com/pic/8211971

I did the same thing but parallel to the front chassis.

I know I have a few I should add but I can think of them.

The fuseholder hole was probably just an oversight (unless there's two small diagonally-oriented holes like originals would have had? Haven't checked out my chassis in that much detail yet......) I'm pretty sure George's original had the ground lug by the inputs (my Super PA also did, and many of the pics I have from researching show one.)

Oh Yeah!! I forgot that I had drill a hole for the HT Fuse Holder I'll add it above!

Thanks,
Mike

ADDED ABOVE:

10.) When testing for volts it is probably best to do so with preamp tubes in to keep the volts down across the board and reduce the risk of frying a cap...

Flames1950 wrote:The fuseholder hole was probably just an oversight (unless there's two small diagonally-oriented holes like originals would have had? Haven't checked out my chassis in that much detail yet......) I'm pretty sure George's original had the ground lug by the inputs (my Super PA also did, and many of the pics I have from researching show one.)

Possible. These flat fuse holders in this amp have a single hole in the center to mount them.

Here are a few pics that may help clarify.

VG

A question which may be entered into the FAQ once correctly answered...

I want to form the caps per Larry/Novosibir's method. Do I understand it correctly that I simply need to put in a 100k/1W resistor somewhere between the point where a wire leaves from the cathode side of the rectifier diodes, and where it enters on the positive side of the mains filter caps? The wire from the rectifier cathode goes to one lug of the standby switch, then the wire from the other lug of the switch goes to the + end of the mains filter, so somewhere between there?

Yeah, I think you can add a 100K across the standby switch and achieve the same thing as disconnecting the wire to the caps.

Don't switch the standby to play position though, because that would defeat the resistor.

Hey gutpile, I think this will be very helpful for my future JTM45/100 build. Would you reupload those pics? Sorry for the necropost too but this is a good thread. Thanks!