[Monolithic]

Hi b0bb,

Do you have a parts link to the caps used in your power supply (circled in yellow)?

Thanks.

 

[b0bb]

Hi b0bb,

Do you have a parts link to the caps used in your power supply (circled in yellow)?

Thanks.

4.7uF Panasonic Polypropylene.
https://www.mouser.com/ProductDetail/panasonic/ecw-fd2w475jb/?qs=9JuRDuJWUh8Qp3Xb43bNnA==

 

[ESL57]

It is in the burn-out period, the positions were corrected for the LT regulator adjustment components, 1uf / 63v capacitors installed, here you can see how small the original Mundorf seems.

 

[Monolithic]

4.7uF Panasonic Polypropylene.
https://www.mouser.com/ProductDetail/panasonic/ecw-fd2w475jb/?qs=9JuRDuJWUh8Qp3Xb43bNnA==

Thanks b0bb!

 

[leondikim]

The regulator replacements, starting from left to right
Belleson SPX17 5V 3A for the primary 5V regulator


3A LT1764 replaces original 1.5A LT1963
2k and 499R Vishay PTN Tantalum nitiride 0.1% 10ppm resistors used to set the voltage


The 2 Auxillary 5V regulators use LT3083, this has similar performance to the LT1963, outputs 3A current.
Design is similar to the LT3042 requiring just 1 resistor to set voltage
100k Vishay PTN Tantalum nitiride 0.1% 10ppm resistors used to set the voltage.

Dear b0bb,
Is Belleson SPX17 5V 3A for the positive output? Also is the output voltage variable from +5V to +30V or +5V fixed? I put a link that I find here.

https://www.belleson.com/store/SPX17-Positive-Output
SPX17 Positive Output

Another question I have is 100k Vishay PTN Tantalum Nitiride 0.1% resistors. Is this one the right one?
https://www.digikey.com/en/products...IAugL6OEBMZIACgCoByADHH4BWAJph+-AMwAhAMrcITIA
PTN0805Y1003BST1 Resistor

Thank you very much!

 

[b0bb]

Dear b0bb,
Is Belleson SPX17 5V 3A for the positive output? Also is the output voltage variable from +5V to +30V or +5V fixed? I put a link that I find here.

https://www.belleson.com/store/SPX17-Positive-Output
SPX17 Positive Output

Another question I have is 100k Vishay PTN Tantalum Nitiride 0.1% resistors. Is this one the right one?
https://www.digikey.com/en/products/detail/vishay-dale-thin-film/PTN0805Y1003BST1/12820683?s=N4IgjCBcoLQBxVAYygMwIYBsDOBTANCAPZQDaIA7AGwAsIAugL6OEBMZIACgCoByADHH4BWAJph+-AMwAhAMrcITIA
PTN0805Y1003BST1 Resistor

Thank you very much!

Fixed +5V for the Belleson

The correct 100k resistor is
https://www.mouser.com/ProductDetail/Vishay-Thin-Film/PTN1206E1003BBT1?qs=q8fegZIhAPsSeL5fyrHpJg==

 

[leondikim]

Fixed +5V for the Belleson

The correct 100k resistor is
https://www.mouser.com/ProductDetail/Vishay-Thin-Film/PTN1206E1003BBT1?qs=q8fegZIhAPsSeL5fyrHpJg==

Thank you!! So is the highlighted area the resistor?

 

[b0bb]

Thank you!! So is the highlighted area the resistor?

The resistor is on the main pc board

 

[leondikim]

This week I finally had the time to install the LT3083 Regulator for the DAC Core Supply.
Some people asked me by private chat to post the install Steps. So here are the steps. This is only valid for version 2 of the 004. ( 4,1V )

!!!! please wait with the installation for what I have to say in the next post !!!!

Take out the secondary Capacitor, and the SET Pin Capacitor



Desolder both resistors :


Install a 82K Metal Film Resistor at the left position, and a 1µF Film Cap where the Set Pin Cap was :


- Remove the LM317.
- Tack the LT3083, and cut of the most left Pin, it's not connected internally anyway.
- Connect the two most right pins.




- Install the LT3083 on The PCB and heatsink
- Install the Secondary Filter Capacitor back where it was :



Thats it

Thank you for sharing your great work. I have a few questions for you

1) I found that two SET pin capacitors are soldered with WIMA capacitors underneath the pcb. After replacing the SET pin capacitors with 1uF film cap, did you solder back the WIMA cap?

2) May I know the 1uF film cap manufacturer/model number? How many did you need? 3 or 2?

3) Did you replace the resistors and the SET pin capacitor where you installed SPX17? If you put the same 1uF film cap and 82k metal film resistor with SPX17, does it mean that I need three 1uF film caps and three 82k metal film resistor?

I appreciate your help!

 

[leondikim]

Add resistors, diodes and caps

Hi b0bb,
Thank your for answering my beginner's question. Here are another questions I have:

1. In the red colored box, what did you connect with a wire shown in the picture? Bypass capacitor?
2. In the yellow colored box, did you use the same resistors (Vishay 100k or 84k based on the generation) that was used in the blue box? If not, could you please tell me what these are?
3. For my clarification, the location on (1) is for SPX17 and the locations on (2) and (3) are LT3083. Is this right?
4. Could you share the part number of LT1764? I see different voltage output 1.8v and 2.5v on two different LT1764 model numbers.

I have been gathering the parts and am looking forward to modding it.
Thank you for your generous help!

 

[b0bb]

Hi b0bb,
Thank your for answering my beginner's question. Here are another questions I have:

1. In the red colored box, what did you connect with a wire shown in the picture? Bypass capacitor?
2. In the yellow colored box, did you use the same resistors (Vishay 100k or 84k based on the generation) that was used in the blue box? If not, could you please tell me what these are?
3. For my clarification, the location on (1) is for SPX17 and the locations on (2) and (3) are LT3083. Is this right?
4. Could you share the part number of LT1764? I see different voltage output 1.8v and 2.5v on two different LT1764 model numbers.

I have been gathering the parts and am looking forward to modding it.
Thank you for your generous help!

1. Connects ground terminal on SPX17 to the DAC's ground.
2. No, keep the stock resistors. The ones in the picture are non standard and not easily obtainable due to part shortages.
3. Yes
4. Not really needed unless you want to use OCXOs, only the military spec version is available at 2.5X the normal price.
https://www.mouser.com/Analog-Devic...s/_/N-5cgac?P=1y9989iZ1yyh4l4Z1z0xww1Z1z0si72

 

[leondikim]

Dear b0bb,
Thank you for your answer. I read again your previous post and found these two resistors you used in the blue box.

• Vishay PTN Tantalum Nitiride 0.1% 10ppm 499 ohm (1206)
• Vishay PTN Tantalum Nitiride 0.1% 10ppm 2k ohm (1206)

Do I find the right ones? It looks like they are recently stocked.
Also, if I don't plan on using OCXOs, I don't have to upgrade from LT1963A to LT1764A? Should I still replace one of the regulators with SPX17? My understanding is that SPX17 supports 3A.

 

[b0bb]

Dear b0bb,
Thank you for your answer. I read again your previous post and found these two resistors you used in the blue box.

• Vishay PTN Tantalum Nitiride 0.1% 10ppm 499 ohm (1206)
• Vishay PTN Tantalum Nitiride 0.1% 10ppm 2k ohm (1206)

Do I find the right ones? It looks like they are recently stocked.
Also, if I don't plan on using OCXOs, I don't have to upgrade from LT1963A to LT1764A? Should I still replace one of the regulators with SPX17? My understanding is that SPX17 supports 3A.

No need to upgrade to LT1764 if you are not using OCXO, those resistors are for the LT1764.

SPX17 is used for DAC 3.3V analog chosen for low noise output.

 

[leondikim]

Thank you! I really appreciate your willingness to help.

 

[Monolithic]

Hi b0bb,

I'm trying to straighten out the input side.

I have a Gen2 board using a Pulsar OCXO. The Gen2 board layout/components are slightly different than the Gen1. Below photo is a stock Gen2 layout.

1) In red circles - are these the two caps that are replaced with 10nF caps (LDBCA2100GC5N0)?

2) In yellow circles - are these the two caps that are replaced with 1uF caps (25MU105MA23216)?

3) In green box - is this the input cap to change to 820uF RNL? (the black values on top of the caps indicate change in values 820uF RNLs/100uF RR7s)

4) In violet box - the current Gen2 resistors are red/red/black/gold, 2.2ohm. I believe you replaced these with 5 ohm (VSMP Z-Foil) on Gen1 (Gen1 originals were 3.3ohm). Would you recommend changing these on Gen2 board and, if so, to what value?

5) In orange boxes - is 5A the positive rail voltage adjustment and is 5B the negative rail voltage adjustment?

6) Where is the input inductor located on the board? Any recommended upgrade parts to avoid saturation with the input cap change?

Thanks again.