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PS503A Mod FF Photos?


Jared Cabot
 

Hi,
Does anyone have a PS503A Dual Power Supply module with the Mod FF (adjustable 5v output) installed?
I'm just looking for some photos to determine the difficulty of retrofitting this mod to my unit.


Thanks!
Jared


Colin Herbert
 

First off, my PS 503A doesn't have the FF Mod, but you can find text relating to the mod at http://w140.com/tekwiki/images/9/91/061-3171-00.pdf. There are no photos, I'm afraid.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jared Cabot via groups.io
Sent: 21 August 2020 02:12
To: TekScopes@groups.io
Subject: [TekScopes] PS503A Mod FF Photos?

Hi,
Does anyone have a PS503A Dual Power Supply module with the Mod FF (adjustable 5v output) installed?
I'm just looking for some photos to determine the difficulty of retrofitting this mod to my unit.


Thanks!
Jared


Stephen
 

May I ask why one would need to modify a PS503A?
Can’t you adjust and fine tune the 20V supply? That’s what i do on mine... 🤷‍♂️


Colin Herbert
 

You have a point, there. I just thought that the +5 VDC supply might give you more current to play with, which is so, but using it in a high-power bay, you have 1 A available to the 0-20 VDC supplies, rather than 400mA. I suppose someone must have thought it a good idea for the folk without a high-power bay.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Stephen
Sent: 22 August 2020 15:18
To: TekScopes@groups.io
Subject: Re: [TekScopes] PS503A Mod FF Photos?

May I ask why one would need to modify a PS503A?
Can’t you adjust and fine tune the 20V supply? That’s what i do on mine... 🤷‍♂️


Stephen
 

On Sat, Aug 22, 2020 at 03:47 AM, Colin Herbert wrote:


You have a point, there. I just thought that the +5 VDC supply might give you
more current to play with, which is so, but using it in a high-power bay, you
have 1 A available to the 0-20 VDC supplies, rather than 400mA. I suppose
someone must have thought it a good idea for the folk without a high-power
bay.
Colin.
This might indeed be the reason. Because otherwise I don’t see what this mod would add to the table...
You’re probably right.


 

On Sat, Aug 22, 2020 at 04:17 PM, Stephen wrote:


May I ask why one would need to modify a PS503A?
Can’t you adjust and fine tune the 20V supply? That’s what i do on mine...
🤷‍♂️
A few reasons come to mind:
1. I may want to use the +/- 20V lines and supply my ECL logic as well (-5.2V nominal). It *is* a triple-voltage supply...
2. I may be using the +/- 20V lines, at the same time wanting to supply my Raspberry Pi 3B+, which doesn't like being fed less than 5.1V (or so).
3. I may want to supply my +/-15V OpAmp circuits while finding supply voltage limits for a connected 3.3V or (TTL) 5V circuit.
4. The reason I just stole from Colin: 5V at 1A from a TM504 (high power slot at the right) or the like.

Raymond


Colin Herbert
 

Wouldn't another power-supply be a possibility? Perhaps another PS503A or something simpler, even. What if you want four power-sources - basically then you do need another power-supply.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Raymond Domp Frank
Sent: 22 August 2020 17:41
To: TekScopes@groups.io
Subject: Re: [TekScopes] PS503A Mod FF Photos?

On Sat, Aug 22, 2020 at 04:17 PM, Stephen wrote:


May I ask why one would need to modify a PS503A?
Can’t you adjust and fine tune the 20V supply? That’s what i do on mine...
🤷‍♂️
A few reasons come to mind:
1. I may want to use the +/- 20V lines and supply my ECL logic as well (-5.2V nominal). It *is* a triple-voltage supply...
2. I may be using the +/- 20V lines, at the same time wanting to supply my Raspberry Pi 3B+, which doesn't like being fed less than 5.1V (or so).
3. I may want to supply my +/-15V OpAmp circuits while finding supply voltage limits for a connected 3.3V or (TTL) 5V circuit.
4. The reason I just stole from Colin: 5V at 1A from a TM504 (high power slot at the right) or the like.

Raymond


Stephen
 

This is exactly what I was gonna say.
Use another power supply... 🤷‍♂️


 

On Sat, Aug 22, 2020 at 06:44 PM, Colin Herbert wrote:


Wouldn't another power-supply be a possibility? Perhaps another PS503A or
something simpler, even. What if you want four power-sources - basically then
you do need another power-supply.
Sure, definitely, I wouldn't want to modify a PS503 *today*. In the past, I may have but reason 2 wouldn't have applied...
In the past, I would have liked to use fewer slots in my TM50x.

Raymond


Eric
 

I hate to be the barrier of bad news but the mod FF only gives a +0.5 -0.5
adjustment not a fully adjustable output.

So 4.5 to 5.5 Vdc

Eric

On Thu, Aug 20, 2020, 9:12 PM Jared Cabot via groups.io <jaredcabot=
protonmail.com@groups.io> wrote:

Hi,
Does anyone have a PS503A Dual Power Supply module with the Mod FF
(adjustable 5v output) installed?
I'm just looking for some photos to determine the difficulty of
retrofitting this mod to my unit.


Thanks!
Jared




J Mcvein
 

So 4.5 to 5.5 Vdc
In ye olde days, enough to test TTL logic circuit at min/max supply voltage.
7805 regs are usually on the low side. -J-
-----Original Message-----
From: "Eric" <ericsp@...>
Sent: Sunday, August 23, 2020 9:26pm
To: TekScopes@groups.io
Subject: Re: [TekScopes] PS503A Mod FF Photos?



I hate to be the barrier of bad news but the mod FF only gives a +0.5 -0.5
adjustment not a fully adjustable output.

So 4.5 to 5.5 Vdc

Eric

On Thu, Aug 20, 2020, 9:12 PM Jared Cabot via groups.io <jaredcabot=
protonmail.com@groups.io> wrote:

Hi,
Does anyone have a PS503A Dual Power Supply module with the Mod FF
(adjustable 5v output) installed?
I'm just looking for some photos to determine the difficulty of
retrofitting this mod to my unit.


Thanks!
Jared




Jared Cabot
 

I understand that Mod FF only gives +/- 0.5V adjustment, but that is enough to account for voltage drop over wires and give a little leeway here and there (say, a little extra for a Raspberry Pi or similar) etc.

I found the manual on the Tek Wiki site, but I was just hoping to find a photo of the physical implementation to see how difficult it would be to retrofit 'just because'.