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Thread: Packard Bell PB450 modifications

  1. #1
    Join Date
    Oct 2017
    Location
    SE Michigan, USA
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    Default Packard Bell PB450 modifications

    Yesterday, I received a package from Digi-Key with the items that I purchased on Friday:

    4x 22uF 6.3V tantalum capacitors (SMD)
    10x 0 Ohm resistors (too small)
    2x 0 Ohm resistors (too darn small)
    2x 3.3V Fixed Voltage Regulators
    2x Voltage Regulator mounting kits
    2x CR1220/BR1220 battery holders (one is on the board and accidentally cut the legs off since I thought it would touch the bare metal on the case, and I was wrong)
    5x 128Kb 28-pin DIP 12ns cache chips (not working since the board only supports 20ns and 15ns SRAM chips).

    Did the modifications on my Packard Bell PB450 motherboard (Packard Bell Pack-Mate 28 Plus), however, I didn't solder the battery holder very well and accidentally trimmed the legs off. Good news is, I bought two of them, same thing with the capacitors, fixed voltage regulators, and the VRM mounting kit. As also seen in this forum: https://www.vogons.org/viewtopic.php...rt=140#p711422

    Voltage regulator mod (cleaned the rest of the flux off, mostly after the picture was taken):



    Battery holder (will fix):



    Gallery: https://imgur.com/gallery/LBoMgt2

    Granted my soldering isn't that great, but, it has improved, and thankfully, I still have a ton of flux left and a few wrapped up solder braid, which did get the old solder off in order for me to install the voltage regulator.

    The battery holder that's installed got a lot of the flux cleaning chemical on there, so I'm going to replace it with the spare I bought and the system says the battery is dead.
    Current retro systems:
    2x Commodore 64 Breadbin 250407 Rev. B and C
    Packard Bell Pack-Mate 28 Plus, aka, the Ultimate Sound Card machine
    iMac G3/600 Graphite, Mac OS X 10.4.11 Tiger, Lubuntu 16.04.3 LTS
    iMac G4/800 Lampshade, Mac OS X 10.4.11 Tiger
    YouTube channel: https://www.youtube.com/c/RetroPCUser

  2. #2

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    Quote Originally Posted by retro-pc_user View Post
    The battery holder that's installed got a lot of the flux cleaning chemical on there, so I'm going to replace it with the spare I bought and the system says the battery is dead.
    White spirit, much cheaper than cleaning stuff. If you dont want the drug, that makes you puke when drinking it, on your PCB left over, then use stuff like "iso propanol". Also much cheaper than cleaning stuff.

    Nice work I really like custom modifications or self-built hardware. Just looking at what others did is amazing to me

    //edit: I guess it is not only in Denmark and Germany, that distillery of white spirit puts this drug into the product. Avoid people from drinking it.

  3. #3
    Join Date
    Oct 2017
    Location
    SE Michigan, USA
    Posts
    376

    Default

    One thing I wish I had was a 3.3V DX4-100 processor to make sure I got the connections set and that the voltage is spot-on.
    Current retro systems:
    2x Commodore 64 Breadbin 250407 Rev. B and C
    Packard Bell Pack-Mate 28 Plus, aka, the Ultimate Sound Card machine
    iMac G3/600 Graphite, Mac OS X 10.4.11 Tiger, Lubuntu 16.04.3 LTS
    iMac G4/800 Lampshade, Mac OS X 10.4.11 Tiger
    YouTube channel: https://www.youtube.com/c/RetroPCUser

  4. #4

    Default

    Quote Originally Posted by retro-pc_user View Post
    One thing I wish I had was a 3.3V DX4-100 processor to make sure I got the connections set and that the voltage is spot-on.
    This means you're using the 3,3V board now with a 5V cpu, or did I get this wrong?

    You could use a Multimeter and measure from PIN1 to PIN3, GND to VOUT. If there is 3,3V at the socket definitely too.

  5. #5
    Join Date
    Oct 2017
    Location
    SE Michigan, USA
    Posts
    376

    Default

    The board has jumpers to select between 3.3V and 5V for the processor. I forgot to test that to make sure it's working. My resistance bridge is just straight-up solder since I purchased the wrong sized 0 ohm resistors...

    //edit: I will check it out after I run errands and fix the battery holder.
    Current retro systems:
    2x Commodore 64 Breadbin 250407 Rev. B and C
    Packard Bell Pack-Mate 28 Plus, aka, the Ultimate Sound Card machine
    iMac G3/600 Graphite, Mac OS X 10.4.11 Tiger, Lubuntu 16.04.3 LTS
    iMac G4/800 Lampshade, Mac OS X 10.4.11 Tiger
    YouTube channel: https://www.youtube.com/c/RetroPCUser

  6. #6

    Default

    Quote Originally Posted by retro-pc_user View Post
    The board has jumpers to select between 3.3V and 5V for the processor. I forgot to test that to make sure it's working. My resistance bridge is just straight-up solder since I purchased the wrong sized 0 ohm resistors...

    //edit: I will check it out after I run errands and fix the battery holder.
    I am not sure if the board will power up without a CPU. Maybe the voltage controlling circuit powers immediately off. This is what happens to one of my single board computers (486) if I power up without CPU. I wanted to see what happens on bus without CPU and attached a logic analyzer.
    There is a 8051-family microcontroller on that SBC that controls voltage regulators and shuts down, if something is wrong.


    I have always been too stingy to buy 0 ohm resistors. Maybe if they call it a "bridge" this would have been something else

  7. #7

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    Quote Originally Posted by retro-pc_user View Post
    One thing I wish I had was a 3.3V DX4-100 processor to make sure I got the connections set and that the voltage is spot-on.
    I've got one if you're interested in it.

    It's an Am486DX4-100NV8T.
    ☀☀☀ Visit Take Another Step for both computer and non-computer related discussions. ☀☀☀

    If you're looking for DS/DD or DS/HD 3" or 5" floppy disks, PM me. I've got some new, used, and factory over-labeled disks for sale.

    There is a crack in everything. That's how the light gets in. -- Leonard Cohen

  8. #8
    Join Date
    Oct 2017
    Location
    SE Michigan, USA
    Posts
    376

    Default

    Did some further inspection of the board, and it turned out to be the jumper was missing on the battery pin header on the motherboard. I ended up swapping the battery holder anyway just in case the chemical flux cleaner damaged the terminals. Now the floppy drive needs attention, but, I'm sure as heck glad that I got the battery to work now, yet the L2 cache is still causing the system to not boot, even though the chips passed the test on my laptop using the EEPROM programming tool and software and gets detected as 128KB (4x 32Kx8 20ns 28 pin, 1x 32Kx8 15ns 28 pin, 64Kx1 15ns 22 pin).

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