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pcdata76
August 20th, 2017, 12:28 PM
During the week-end, I've decided to remove the cabinet of my newly bought 5153 (together with a late-model 5160) to check inside and clean the internals thoroughly because it was filling the room with heavy smoke odor within minutes after operation. Here, IBM gear is usually used mainly in public and private companies due to the high selling price compared with the clones and the one that i've bought was not an exception (It had inventory tags of a company on the side of the case) Smoking was allowed in public and closed buildings during these years, so it is expected that they smell like an ashtray.

Other issues are:
-Brightness and contrast potentiometers were flaky
-focus was a bit off (It's my feeling and may not be an issue with the monitor. I didn't use a monitor having such a coarse dot pitch ever and the only other CGA monitor that i have is a Sony Trinitron having very fine (0.24mm) pitch and giving very clear picture with clearly visible scanlines.)
-white was a bit blue tinted.

So I've removed the case, discharged the tube (nothing was left after a day since last operation) and removed all connectors, boards and tube from the casing. My initial intention was just the washing the casing, boards and the tube and spraying the potentiometers with contact cleaner, but after seeing some heat damaged capacitors (see photos below, plastic sleeve of some of the capacitors has been shrunk down and they are located usually very close to a power resistor) and rust at the bottommost metallic parts probably due to water intake, I've decided to do a complete overhaul. Some part of the power supply PCB was also seriously blackened (actually burned) due to local excessive heat and there was cold solder joints in this region too.

Mainboard:
40385

Power Supply Board:
40386
40387

CRT Board:
40388

I've removed electrolytic caps from power supply board and measured them. Some of them were close to the spec but the rest were at least two to three times high in ESR. I also verified resistors and film capacitors in the heat affected region in the power supply board and they were all in spec.

Since obtaining good quality capacitors locally (i mean within the country by local) is almost impossible, I've made the list of the capacitors and will order them from a reputable online electronic component store. Before placing the order, i've decided to add my 5151 and 8513 recovered from electronics recycling center last year to the list, I've dismantled them and created the list of capacitors. I wanted to share the list here for a future reference, since they could be different than service manual sometimes. For example, my 8513 is an early model (S/N starting with 23-XXX) and service manual found on the net covers only the late revisions (S/N having 72-XX prefix) and they have totally different circuit layout and components in compared with mine except the model name.

Anyway, here is the list:

IBM 5151 (220V Version, probably only mains transformer is different in 110V versions)
5151 (https://www.dropbox.com/s/y6twtmuj0r0gen4/5151.pdf?dl=0)
Note that C505 is a special kind of capacitor, bipolar and low ESR electrolytic. It is not easy to get them, so i'm planning to use some paralleled film caps in place of that capacitor.

IBM 5153 (100/240V version)
5153 (https://www.dropbox.com/s/olxmp5huf8bbe37/5153.pdf?dl=0)

IBM 8513-002, S/N starting with 23 (200-240V Version)
8513 (https://www.dropbox.com/s/7odtzhubjzjndyf/8513.pdf?dl=0)

Before ending the topic, i just want to tell few more words about my cleaning procedure.

-Disassemble everything (casing, boards, tube, all other things like degauss coil and switches etc.) Make photos during disassembly, it really helps during reassembly especially if device contains too much and various kinds of fasteners. Note the location of the connectors too.

-Wash the casing using warm soapy water. Rub the outer parts of the casing (except tags and labels) using Cif (a cream detergent having lightly abrasive material inside which is often used here in the cleaning of sinks and bathtubs) with a brush.

-Clean the tube thoroughly using wet towels but be careful to not rub much the bell area (it has graphite (aquadag) coating which is required for proper operation and could be easily removed by heavy rubbing) If the tube is very dirty, i usually wash it too under warm water by rubbing with a soft brush. Leave tube to dry (especially complete drying of the deflection coils need some time) Be also careful to not damage to the delicate neck of the tube. Hold CRT always using two hands from the sides firmly, be careful to not drop! Never ever lift the tube from the neck. Also, always put a soft and thick cloth under the face of the tube during cleaning/drying periods to prevent scratches.

If boards are dirty beyond vacuum cleaning as in the current case with smoke residue (Take necessary ESD precautions during the job):

-Desolder parts like coils and transformers (including flyback transformer) in which water could be trapped in for long time and causing issues

-Clean desoldered parts using wet towel.

-Wash the circuit board with warm soapy water and using a soft brush (I prefer 1" paintbrush for this job)

-Rinse circuit board using demineralized water and/or IPA.

-Leave circuit board for at least a day (in summer, i keep more in winter) in a warm place to dry.

-Resolder desoldered parts, perform other component replacements/repairs if needed.

-Reassemble everything.

I'll picture the whole assembly procedure and post in the forum after completion of the recapping job.

Flamin Joe
August 20th, 2017, 06:47 PM
Great work. The cap list will come in very handy as I'm planning on doing a full recap/clean for my 5153.

Just one problem though, the cap lists for the 5153 and 8513 are coming up very small and as a result they are unreadable. The other images however including the 5151 cap list are fine.

pcdata76
August 20th, 2017, 08:16 PM
Thank you for the feedback, corrected the links.

paul
August 21st, 2017, 05:19 PM
If you have any further concerns with the 5153 power supply it's not to hard to replace it with an industrial unit. I did so just to get reliable operation on 230VAC. The OEM unit is not a very efficient design.

bobba84
August 21st, 2017, 05:39 PM
Thanks for this valuable info! Even though I didn't use it, as opening my 8513 yesterday showed that the problem was detached wires on the power switch (lol) - but I'm sure these will come in handy in the future!

Bobby.

pcdata76
August 22nd, 2017, 11:49 PM
If you have any further concerns with the 5153 power supply it's not to hard to replace it with an industrial unit. I did so just to get reliable operation on 230VAC. The OEM unit is not a very efficient design.

It is definite. I think that PS consumes half of the total mains power itself due to the inefficiency. My first intention was also doing like you after reading your thread, but couldn't managed to find any 115V DC output power supply neither locally nor online. Only 48V DC at most :/

Anyway, I've made the list of the capacitors inside of the 5155 CRT and power supply too, here are the links:

5155 CRT (https://www.dropbox.com/s/wzx16ko3v0oralf/5155%20CRT.pdf?dl=0)
5155 PS (https://www.dropbox.com/s/ocsw5rev3zroo9s/5155%20PSU.pdf?dl=0)

PS: PS and CRT units of the 5155 are made by Zenith and they've been built using all good japanese caps (ELNA, Nichicon, Marcon etc.). I'm sure that 95% of them are still in (or at least near) spec. Last time when i was repairing my Sony CGA monitor from mid80's, all of the caps (of course all japanese) which i've suspected were measured better than new chinese/taiwanese stuff, i.e. lower ESR and decided to keep them in place :)

paul
August 23rd, 2017, 04:50 AM
..couldn't managed to find any 115V DC output power supply neither locally nor online. Only 48V DC at most...Yes, they are very hard to find but this one is still available in case you change your mind. You simply adjust it up to 115VDC at the pot.
http://www.ebay.com/itm/New-AC100-240V-to-110VDC-0-9A-100W-DC-Regulated-Switching-LED-Power-Supply-/182726003959

ibmapc
August 23rd, 2017, 07:09 AM
I assume your "capacity" column is μF ?
Anyway, this is good info. I have a 5155 with a monitor that is wonky when first started but straightens out after a while, so, I've been planning a re-cap for it.

pcdata76
August 24th, 2017, 12:02 AM
I assume your "capacity" column is μF ?
Anyway, this is good info. I have a 5155 with a monitor that is wonky when first started but straightens out after a while, so, I've been planning a re-cap for it.

Yes, all are in F. I actually forgot to define units.

Note that I only listed the electrolytics. Other low capacitance film/ceramic capacitors are not listed and they usually no need to replace unless failed. The only exception to the case is the famous RIFA X2 suppression caps. If any of your unit have any of these yellow colored X2 caps, replace them asap before letting them to blow and fill your room with nasty smoke.

40438

Hopefully couldn't identified any of them in my units. Actually I was expecting to see them in 5155 power supply but they were in different brand, so didn't bother to replace.

pcdata76
November 5th, 2017, 05:14 AM
UPDATE:

I've replaced all of the electrolytic capacitors of monitors and power supply of 5155. I've measured ESR and capacitance of all removed caps as a reference and compared with the newly bought japanese (nichicon, rubycon, nippon chemicon) caps.

Instead of replacing them entirely, only suspected caps could be replaced by using this reference. Note that all of the bad caps are located near a strong heat source. If possible, you can relocate capacitor or heat source to extend the life of newly installed capacitors.

5151:

Measurements: https://www.dropbox.com/s/dkaiunkgaxeb07d/5151_comp.png?dl=0

Values in the remarks field are the measurements of new caps, at the right of the table are the measurements of originals. Could be seen that all of the caps except C505 are in spec. C505 is a bipolar electrolytic but it is not easy to source it. That's why, i've used two parallel connected 8,2uF film caps instead. To make the modification, i had to drill two additional holes to the pcb.

41768 41769 41770

PS: Almost all of the connectors on the board are in the same type. Don't lose the labels glued on the connector shell and install them back by matching the tags with silkscreen on the pcb.

5153:

Measurements: https://www.dropbox.com/s/aoe3iwkc5bi48wc/5153_comp.png?dl=0

Values in the remarks field are the measurements of new caps, at the right of the table are the measurements of originals. C507, C537 and C567 in RGB drive stage are totally dead and should be replaced. They are located very close to the power resistors but there is nothing much to do for relocation. Another totally dead capacitor is C509 on CRT board, which is also located very close to a power resistor (filament current limiting resistor). I've relocated that resistor after replacing the capacitors. C812 in power supply is also measured high in ESR so replacement is recommended. Rest of the caps are in spec and could be left if monitor is working good.

Replacement of the dead capacitors cured the occasional blueish-tint change issue but focus is still not good enough at the best focus point. Most probably tube is aged beyond its service life and should be replaced.

41773417744177541776

8513

Measurements: https://www.dropbox.com/s/jysqy4tpbbs18tv/8513_comp.png?dl=0

Values at the first column next to the table are the measurements of new caps, the second column are the measurements of originals. None of the caps in 8513 were off-spec. I've done a totally unnecessary job :D
41780

5155
Despite being the oldest vintage computer in my ownership, all of the caps were still measured good despite its age.

Measurements of CRT mainboard: https://www.dropbox.com/s/3mycr5wvd43k1sq/5155%20CRT_comp.png?dl=0
Values in the remarks field are the measurements of new caps, at the right of the table are the measurements of originals. None of the caps were off-spec. Original caps were also all-japanese. There is also a bipolar electrolytic cap in this monitor as in the case with 5151. I've replaced it again with a 10 uF film capacitor (could be seen at the right bottom corner of the picture).

Measurements of Power Supply: https://www.dropbox.com/s/jtsho7ygp00daw3/5155%20PS_comp.png?dl=0
Values at the first column next to the table are the measurements of new caps, the second column are the measurements of originals. None of the caps were off-spec. Original caps were also all-japanese.

417774177941778

clh333
January 8th, 2018, 03:40 AM
Thanks again for this information. Repair of a 5153 is on my to-do list.

-CH-

pcdata76
January 8th, 2018, 09:11 AM
Thanks again for this information. Repair of a 5153 is on my to-do list.

-CH-

You're welcome. Particularly the power supply and color drive sections are problematic in 5153 monitors. Power supply dissipates too much heat (even more in 230V version) and some of the capacitors in color drive section are loceted very close to the big-wattage power resistors. Rest of the capacitors are usually fine. If you don't plan a total recap, which is often unnecessary, I'd replace at least the mentioned caps.

Bernie250
January 11th, 2018, 09:14 AM
Awesome post, thank you!
Very informative, very entertaining.

offensive_Jerk
January 11th, 2018, 12:16 PM
Any 5154 info?

pcdata76
January 11th, 2018, 09:06 PM
If i have the chance of getting a 5154 one day, I'll update the topic. It is impossible to find any working or non-working sample locally here and ebay prices are insane (beside the possibility of physical damage during overseas shipping).

Bernie250
January 16th, 2018, 11:50 AM
About your recap job on the 5151.

UPDATE:
.....Values in the remarks field are the measurements of new caps, at the right of the table are the measurements of originals. Could be seen that all of the caps except C505 are in spec. C505 is a bipolar electrolytic but it is not easy to source it. That's why, i've used two parallel connected 8,2uF film caps instead. To make the modification, i had to drill two additional holes to the pcb.


Here in Holland we do not use the term film caps.
I think you are referring to what we call 'folie-condensatoren' (foil-caps).
Similar to those I used to replace the X2 Rifa's in my 5160 PSU.

I do not recognize the markings on the caps.
Do you have a part number on those?

pcdata76
January 16th, 2018, 09:41 PM
Exactly, they are called Folienkondensatoren in German also. At the time when these monitors were built, they were non-existent at capacities over few microfarads in reasonable sizes but nowadays, they are quite widespread so i tend to use them as a replacement of bipolar electrolytics below 20-25 uF. They are similar to the X2 caps that you've mentioned, but with different specs. They also have very low ESR in compared with electrolytics (for the particular location of that capacitor in 5151, low ESR is desired)

Important parameters in the selection of that capacitor are:

Capacitance: Total capacitance of the paralleled group of caps (or single capacitor if you can get) should be close to the 18 uF (+/- 2 uF) I've used two 8.2 uF (measured around 17uF in parallel) caps but you can also use one 18uF/20 uF, two 9uF or three 5.6uF caps in parallel)
Voltage: Should be at least 25 V (but film capacitors at that capacity usually have a voltage rating starting from 60V, so it is not a concern in our case)
Size: Should be small enough to fit the place of the original capacitor. Lower voltage models have smaller size, so try to get 60V-100V ones maximum.

Caps which I've bought are similar to the ones at the following link: https://www.digikey.com/product-detail/en/panasonic-electronic-components/ECQ-E2825KF/EF2825-ND/56525



About your recap job on the 5151.


Here in Holland we do not use the term film caps.
I think you are referring to what we call 'folie-condensatoren' (foil-caps).
Similar to those I used to replace the X2 Rifa's in my 5160 PSU.

I do not recognize the markings on the caps.
Do you have a part number on those?