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projects:tek222bat [2017-11-04 06:38]
robert
projects:tek222bat [2020-05-31 11:32] (current)
robert [Tektronix 222 Battery Pack]
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 ===== Tektronix 222 Battery Pack ===== ===== Tektronix 222 Battery Pack =====
  
-For those of you interested in a multimedia audio-visual experience, there is a little overview video of the battery pack of youtube [[https://​youtu.be/​LJ2VS3aohV0|here]].+For those of you interested in a multimedia audio-visual experience, there is a little overview video of the battery pack on youtube [[https://​youtu.be/​LJ2VS3aohV0|here]]. 
 + 
 +If you would like to buy a ready-made replacement battery unit based on this design, N0DY Electronics is building and selling them [[https://​www.n0dy.com/​product/​tekcharger/​|here]].
  
 ==== Introduction ==== ==== Introduction ====
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 ==== Overview ==== ==== Overview ====
-Starting out, I new that I had to (or wanted to) build a circuit that wraps around one or more lithium cells and makes them behave like the original 8V SLA battery as far as the scope is concerned. The way I chose to achieve this is shown in the following diagram:+Starting out, I knew that I had to (or wanted to) build a circuit that wraps around one or more lithium cells and makes them behave like the original 8V SLA battery as far as the scope is concerned. The way I chose to achieve this is shown in the following diagram:
  
 {{ :​projects:​scope-bat.png?​direct&​400 |}} {{ :​projects:​scope-bat.png?​direct&​400 |}}
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   * PCB Gerbers {{:​projects:​scope-bat1.zip?​linkonly}}   * PCB Gerbers {{:​projects:​scope-bat1.zip?​linkonly}}
   * Schematic and PCB layout (DipTrace 3.1) {{:​projects:​scope-bat1-design.zip?​linkonly}}   * Schematic and PCB layout (DipTrace 3.1) {{:​projects:​scope-bat1-design.zip?​linkonly}}
 +  * DXF files for acrylic case parts {{:​projects:​bat-acrylic.dxf?​linkonly}}
  
-The above files are for Revision 1 of the board, which I have not yet built and tested. However, the only changes from Revision 0 are fixes for few mistakes so hopefully it should work without any issues. +The above files are for Revision 1 of the board, which has been built a number ​of times and proved ​to be robust.
- +
-If for any reason you'd like the Revision 0 design files you can find them here: +
-  * Schematic PDF {{:​projects:​scope-bat-sch0.pdf?​linkonly}} +
-  * Bill of Materials {{:​projects:​scope-bat-bom.csv?​linkonly}} +
-  * PCB Gerbers {{:​projects:​scope-bat-gerbers0.zip?​linkonly}} +
-  * Schematic ​and PCB layout (DipTrace 2.9) {{:​projects:​scope-bat-design0.zip?​linkonly}} +
- +
-If you decide ​to build the circuit from the Revision 0 board / schematic, you need to apply the following fixes: +
-  * Add a 1MΩ pull-up resistor on OUTA (pin 1) to Vs (pin 5) of the LT6700. +
-  * Add a 4.7µF ceramic capacitor in parallel with the decoupling capacitor of the LT6700. +
-  * Add a 10MΩ feedback resistor between OUTA (pin 1) and INA, INB (pins 3 and 4) of the LT6700. This increases the hysteresis voltage. (optional) +
-  * Add a 1µF ceramic capacitor in parallel with each of the electrolytic capacitors.+
  
 {{ :​projects:​bat-switcher-top.jpg?​direct&​400 |}} {{ :​projects:​bat-switcher-top.jpg?​direct&​400 |}}
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 The datasheet does mention that the reference is sensitive to noise, but I didn't expect it to have that kind of effect. Adding a 4.7μF decoupling cap on the comparator in parallel to the existing 100nF solved that issue. If I were to re-spin the board, I'd probably add an RC filter on the supply line, just to be on the safe side. The datasheet does mention that the reference is sensitive to noise, but I didn't expect it to have that kind of effect. Adding a 4.7μF decoupling cap on the comparator in parallel to the existing 100nF solved that issue. If I were to re-spin the board, I'd probably add an RC filter on the supply line, just to be on the safe side.
- 
projects/tek222bat.1509788298.txt.gz · Last modified: 2017-11-04 06:38 by robert