DB54 - 2254 style compressor {update 22.10.19}

[Brian Roth]

The highest voltage anywhere in a 2254 will be 24 Volts from the power supply. The voltages in that section of the BA185 will be a tiny fraction of that.

Bri

 

[MoJo]

Good point Migs 31!

 

[MoJo]

The highest voltage anywhere in a 2254 will be 24 Volts from the power supply. The voltages in that section of the BA185 will be a tiny fraction of that.

Bri

Thanks Brian, I will get the ones you mentioned for the second kit I have.

 

[MoJo]

Hi everyone,

I have a question on the BA191 pcb build; According to the BOM C14 is 5uf/25V electrolytic capacitor in radial configuration, but I can only find 4.7uf/25V in radial. I did find 5uf/25V in axial configuration. What do you think? Which one should I use?

And thanks Migs, I definitely am having fun!

 

[scott2000]

if height/size is ok do you have enough leads on the axial to just mount them vertically? I've done it before with some heat shrink added to the leads

 

[MoJo]

if height/size is ok do you have enough leads on the axial to just mount them vertically? I've done it before with some heat shrink added to the leads

Thanks for your reply Scott. So I assume that you are saying there would be an advantage to using the 5uf over the 4.7uf. Is my assumption correct?

 

[scott2000]

Thanks for your reply Scott. So I assume that you are saying there would be an advantage to using the 5uf over the 4.7uf. Is my assumption correct?

I'm not familiar with this project. I'm pretty sure 4.7uf caps were available when this project was realized .. Couldn't tell you why they wouldn't use them. Maybe someone familiar with this will have an answer. Seems like pretty tight tolerance....

 

[MoJo]

I'm not familiar with this project. I'm pretty sure 4.7uf caps were available when this project was realized .. Couldn't tell you why they wouldn't use them. Maybe someone familiar with this will have an answer. Seems like pretty tight tolerance....

Thanks Scott. I'm hoping...

 

[thelivingroom]

Hi everyone,

I have a question on the BA191 pcb build; According to the BOM C14 is 5uf/25V electrolytic capacitor in radial configuration, but I can only find 4.7uf/25V in radial. I did find 5uf/25V in axial configuration. What do you think? Which one should I use?

And thanks Migs, I definitely am having fun!

In situations like this I’d go with the 4.7uF, order 10+ for the price break from Mouser, then measure them and pick the one(s) closest to 5uF if I want to be precise. I had to do this same thing recently while rebuilding my Farfisa. Depending on its function in the circuit, it may not matter though. With the 20% tolerance accounted for, I’d imagine they can be anywhere from 4-6uF and be fine.

 

[Ilya]

4.7 vs 5 uF are basically the same. One is an older standard, another is a newer one. You can put in whatever you have at hand

 

[MoJo]

In situations like this I’d go with the 4.7uF, order 10+ for the price break from Mouser, then measure them and pick the one(s) closest to 5uF if I want to be precise. I had to do this same thing recently while rebuilding my Farfisa. Depending on its function in the circuit, it may not matter though. With the 20% tolerance accounted for, I’d imagine they can be anywhere from 4-6uF and be fine.

I definitely will do that! Thanks for the advice.

 

[MoJo]

4.7 vs 5 uF are basically the same. One is an older standard, another is a newer one. You can put in whatever you have at hand

Thanks for the perspective Ilya!

 

[MoJo]

Hi Everyone,

Does anyone know the correct power switch to order for this build? The designer specified the wrong part number (A101MD9AG04 - it is a right angle switch).

 

[MoJo]

Hi Everyone,

Does anyone know the correct power switch to order for this build? The designer specified the wrong part number (A101MD9AG04 - it is a right angle switch).

No worries, I just cut off the right angle part of the solder legs and it fit just fine.

 

[MoJo]

Hi Everyone,

Does anyone know what, if anything, goes into the two little holes between the R3 resistor and the 3 pole green connector? It is not labeled, and I have installed everything from the BOM.

 

[MoJo]

Hi Everyone,

Does anyone know what, if anything, goes into the two little holes between the R3 resistor and the 3 pole green connector? It is not labeled, and I have installed everything from the BOM.

Sorry, here is the picture:

 

[MoJo]

Sorry, here is the picture:

It is the PSU circuit board.

 

[JMan]

At a glance, those appear to be pads to test the PSU voltage. In the picture you attached, we can see that the lower of the two pads connects to the ground plane or 0v, and presumably the upper pad connects to the VDC output. You can confirm this with a simple continuity test using your multimeter. Since you used a screw terminal style connector, you actually don't need these pads at all to measure the voltage, since you can simply measure between the screws on the connector itself.

At any rate, no, no component goes to those pads. Looks like your PSU is complete.

Unrelated, do be aware that the trimpot that you chose is a side adjust package rather than a top adjust, so you might find it is slightly awkward to work with.

 

[MoJo]

At a glance, those appear to be pads to test the PSU voltage. In the picture you attached, we can see that the lower of the two pads connects to the ground plane or 0v, and presumably the upper pad connects to the VDC output. You can confirm this with a simple continuity test using your multimeter. Since you used a screw terminal style connector, you actually don't need these pads at all to measure the voltage, since you can simply measure between the screws on the connector itself.

At any rate, no, no component goes to those pads. Looks like your PSU is complete.

Unrelated, do be aware that the trimpot that you chose is a side adjust package rather than a top adjust, so you might find it is slightly awkward to work with.

Thanks so much JMan. So should I be able to measure 30VDC once this is connected to the power transformer? Also, I thought the same thing about that trimpot, but all of the trimpots in the BOM were sidewinders. I'll be super careful and put some cardboard between my screw driver and the components in close proximity to that trimpot

 

[JMan]

I think you will be looking for 24 VDC after adjustment, but the build docs should tell you for sure.

For the trimpot, you might want to grab one of these. I find it very helpful and much less prone to hazards like accidental shorts than a screwdriver, although not absolutely necessary.