1081 build should this be a meta?

Gus · Jan 29, 2005

I am starting to stuff the big board by TT. I still need to order alot of parts. I wonder who will be the first to finish one?

First I am using 220uf 25 volt radials for the 100uf at 25V and 150uf at 16V. There are a few reasons for this.

One its easier/cheaper to get 16 of one type.

Two The old timers here might know, but I will post it anyway. About 15years ago electros started to be close to the real uF marking on them. I often find new caps to be just UNDER the marked value. I learned this from measuring caps over the last 20 or so years.

Before about 15 years ago you could/would find the cap marked as 100uf to be 150uf to 200uf.

The 1081 was designed in 1972 so the 150ufs might have been more like 220uf when new. The 100uf are PS bypass more is often better.

Board Questions C26, R29 and pin 5 connections? C28, R35 and pin 5 connections?

Can anyone take a good close up of the EQ caps?

Please some feedback from the possable builders

Gus · Jan 30, 2005

Next question How do L1 and L2 get mounted?

Is anyone building this???????????????

tommytones · Jan 30, 2005

The inductors get soldered down by the pins (originally)...this will depend on which ones you use.

As for your last 2 questions above, what about the caps and pins??

tommypiper · Jan 30, 2005

I think Gus may be asking, what is the orientation of the inductors on the board? From memory, there is a white dot on each inductor to show which side goes up or down. The inductors are not symmetrical, though the pins are. So they can physically be mounted in two positions, rotated 180 degrees. But if you mount the inductor 180 degrees rotated from the intended orientation, you will not get the intended taps and results. I've been waiting for someone to address this question...

The original inductors in original modules also have white dots. Can someone show pix of the orientation?

The comments on the caps are interesting, Gus.

cheers,
t

Gus · Jan 30, 2005

Only one of the inductor types has a white mark in a corner the other does not.

I was not as clear in my post.

The 9047 does not have a dot on one corner. On one corner 4 pins have wires attached the other corner only has one wire.

The 9048 has a dot in the corner that has all 4 wires attached to the pins and the other corner has one wire.

I would GUESS the the 9047 corner with the 4 wire should have a white dot but I am not sure.

Looking at the board reading the letters and numbers right side up, what way do the dots go, top left or bottom right?

C26 R29 look like they share one hole? as well as pin 5 and the other side of R29

C28 and R35 look to share one hole? again pin 5 and R35

TT again thank you for the work you have done with the PCBs!

I can figure out the questions I am asking: however I think the questions I have asked might cause some other builders problems.