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Recent content by andrew96

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    IBM 5153 (CGA monitor) line voltage range

    OK so the HA11235 chip arrived and fitted, I still cannot get it to lock on a 50hz signal, so looking at the vertical hold circuit against circuits of old tv's of the same era and the datasheet of the chip I came up with a plan!!! R307 is currently a 6.2K resistor so lowered this to a 4.7K...
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    IBM 5153 (CGA monitor) line voltage range

    Ok, so how this IBM monitor came about! I have one of these little beauties as I mess with old arcade boards and these are great for doing tests from the CPU point of view! Now the programmers station where you can program your own tests into it was supplied with a monitor / graphic card and...
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    IBM 5153 (CGA monitor) line voltage range

    I did find this in the ibm 5153 monitor specifications, so it should lock fine
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    IBM 5153 (CGA monitor) line voltage range

    picture just rolls and wont lock, applying sync and there is no attempt for it to lock even though there is sync at the chip, no I don't have a pc cga card, this is on a CGA pattern generator which I can change the syncs to be positive or negative 1v or TTL compatible plus mixed syncs too, and R...
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    IBM 5153 (CGA monitor) line voltage range

    I suspected Q302 and Q303 to be faulty and sure enough they both had a base emitter short! so out they came along with Q301 just to be sure! to my surprise they all tested ok!!! so looking again D302 and D303 were short! D301 was also tested just in case but was fine! again the standard 1N4148...
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    IBM 5153 (CGA monitor) line voltage range

    So power supply back in the monitor, time to power it up but still with my adjustable psu, and I get this... frame collapse! I guess when the counterfeit transistor went in the psu it spiked the 115v line as well as this WAS ok before that point! in the words of farher ted.... SO more...
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    IBM 5153 (CGA monitor) line voltage range

    Thanks Paul, although mine does have more holes in the metal case that the standard one and there are some component changes for the 230v psu which appears to keep the heat down, but there is lots of room to put a small fan to blow air through the psu if needs be so will keep a eye on it for...
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    IBM 5153 (CGA monitor) line voltage range

    Everything now fitted, powered it up with my dc current limited power supply! at just over 70v it started to spring to life and at 95v got the full 115v output from it! it seems to regulate fine and am now back to where I was originally with it! just got to pluck up the courage to apply full...
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    IBM 5153 (CGA monitor) line voltage range

    New fusible resistors have arrived, I ended up buying NFR1W10R and NFR1W2R2 fusible metal film resistors once bent into shape and length.. not much more to do now!!! :onfire:
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    IBM 5153 (CGA monitor) line voltage range

    The 3R3 10W resistor on the long standoffs appears not to be around these days, so what I did was to buy a normal axial 10w leaded variety, top resistor is the original bottom is the leaded type I then cut the standoffs off and spaced them the same distance apart as the original, wrapped the...
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    IBM 5153 (CGA monitor) line voltage range

    Don't get these! they are far too small! discovered it is 1w fusible resistors actually fitted on the pcb, I managed to work out the numbers written on them, the first (1) is for 1w then the value (10) and then the (0) is the multiplier, so 1w 10r = 1100 now for the 1229, well again the first...
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    IBM 5153 (CGA monitor) line voltage range

    OK well on doing some research, I have found the diodes with just a black band such as D812, D813, D817 to be 1S1555 (35v 300ma general purpose diode) and the marked diode with a 'T3' D820 to be a 1S1553 which has a 70v 300ma rating general purpose again, so easily able to substitute both with...
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    IBM 5153 (CGA monitor) line voltage range

    bigger view of the diode! I believe them to be made by Hitachi as all the other semiconductors appear to be. the closest I have found so far marked with a '3' is a 1SS199 but the cathode band is green and not black, also the diode package is too small! the search continues......
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    IBM 5153 (CGA monitor) line voltage range

    I have now managed to identify all except one diode! looks like it has a '3' on it and a curved type of 'T' it is Do-35 case style and resides in position D820 in the power supply board. any one have any idea what this diode is?? it is all that is stopping me getting this running! any help...
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    IBM 5153 (CGA monitor) line voltage range

    So before I cut the top off the old transistor, here it is pictured next to 2 I believe to be genuine 2SD1186 transistors! the 1186 is slightly better as has a higher collector emitter breakdown voltage and for me was slightly easier to get hold of than the 1185.
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