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IBMU Repairs


Bob042

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This morning before going to work I pulled one of the cards and hey presto, I don't have an ID problem because its stamped on the card which pec module it is! The card I pulled was the filter module pec (far left from front) and it appears perfect, no sign of damp damage at all. The limited info I have is that this is not one of the problem area cards.

 

I'll put some pics up tonight.

 

Bob

 

As promised below;

 

IBMU Filter module.jpg

 

Above is the filter pec, this card is not normally known to be a problem according to my source.

 

IBMU Filter pec NSN.jpg

 

Filter pec NSN if anyone needs it.

 

The next pec from the left is the PSU, big piece of kit with cooling plate, which I will remove in due course, this is one of the common problem areas, details to follow, see below;

 

IBMU PSU card.jpg

 

Third card from left is one of 2 Driver modules, they are both the same, same NSN, not normally associated with problems according to my source notes, see below;

 

IBMU Driver module_1.jpg

 

IBMU Filter pec NSN.jpg

 

Next from the left (fifth) is the Analogue module which is a problem area, see below. I will detail the problem tants later.

 

IBMU Analogue module.jpg

 

Got to go, Wife chasing me!

 

Regards

 

Bob

 

PS, NEED SOLDRING IRON, any recommendation's? Thinking of 30W variable temp. I know I need solder sucker too. Will be using standard 60/40 tin lead solder.

Edited by Bob042
adding pics of IBMU cards
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The Analogue module problem areas according to my limited info are the 10uF 25V tants C1, C9 (below C12), and C12 as shown below;

 

IBMU Analogue card problem tants C8, C9, C12.jpg

 

Also C5 & C8, again 10uF 25V as seen below;

 

IBMU Analogue card problem tants C5 & C8.jpg

 

Next is the Logic module, which is the far right one with the blue input loom (which can be disconnected as previously described) as seen below, note the interesting repair with the cable tie!

 

IBMU Logic module.jpg

 

Apparently there is only one problem tant on this, C1, 33uF25V, see below;

 

IBMU Logic module problem tant 33uF C1.jpg

 

As previously mentioned, the other problem area is the big PSU card which I will disassemble this weekend and post the pics as well as details of the problem tants. Also some more info on the Analogue card to come with advice wanted on how to test.

 

Anyone any soldering iron recommendations??

 

Regards

 

Bob

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Bob

 

I always use the Weller temperature controlled static protected irons - got issued with one on my first day at work and they have always been reliable and never destroyed anything (they have an earthed tip so are static safe if correctly installed). The WES series are I think the current ones and are between £50 and £100 on e-Bay - I still love my old EC4100M controller with EC1301 iron that I bought from stores at work about 20 years ago.

 

The cable tie is probably not a repair - if the chip is the EPROM holding the IBMU firmware it needs to be socketed for upgrades and then needs to be secured so the chip stays in despite the rigours of military use.

 

These days there are good low ESR electrolytics in similar sizes to the tants that dont have the same failure modes so you should probably consider replacing with 10uF rated at least 30 volts - something like: http://www.rapidonline.com/electronic-components/10uf-35v-5mm-micromin-electro-capacitor-11-1512

 

Best Regards

 

Iain

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Just to give a bit of perspective to all this, here is the radio fit in my LWT FFR, 19 HF 27, contract & build date 1979, ex Gurkha Field Force HQ & Sig Tps, Hong Kong 1980-1997;

 

 

19HF27 Radio fit_1.jpg

 

Everything is in full working order - except you know what, hence I'm a bit driven about it.

 

In the URS battery box are a pair of 15 month old Hawkers for the big sets;

 

19HF27 Radio Batteries connected through to the URS terminals.jpg

 

Today I posted my VMARS membership application.

 

Regards

 

Bob

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Bob

 

I always use the Weller temperature controlled static protected irons - got issued with one on my first day at work and they have always been reliable and never destroyed anything (they have an earthed tip so are static safe if correctly installed). The WES series are I think the current ones and are between £50 and £100 on e-Bay - I still love my old EC4100M controller with EC1301 iron that I bought from stores at work about 20 years ago.

 

The cable tie is probably not a repair - if the chip is the EPROM holding the IBMU firmware it needs to be socketed for upgrades and then needs to be secured so the chip stays in despite the rigours of military use.

 

These days there are good low ESR electrolytics in similar sizes to the tants that dont have the same failure modes so you should probably consider replacing with 10uF rated at least 30 volts - something like: http://www.rapidonline.com/electronic-components/10uf-35v-5mm-micromin-electro-capacitor-11-1512

 

Best Regards

 

Iain

 

Hi Iain,

 

Have had a look at the Weller gear, wow! very nice but by the time I've got all this kit I might as well buy another IBMU from a certain gleebay trader which is not what I want to do (mine do not come from him). Do I really need an ESD iron? If so then fair enough. Unfortunately our work ones are not suitable as we deal with LV switchgear and traction products. We used to build for BT with all the fine stuff but no longer so the irons have all gone with except a couple which are not suitable.

 

Bob

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Bob

 

An ESD safe low voltage iron is best around CMOS chips so certainly for the logic board - most anything else is OK with any old iron as long as it is not too big and too hot (I would say 0.1" point and 360 deg C are the upper limits) - a file and a piece of brass rod will result in a suitable tip for most cheap irons so it is really the temperature that needs checking.

 

If it isnt earthed for ESD (be very suspicious if it has a 2 wire power lead) touching the tip to something that is earthed will clear any static charge. If the iron has a direct mains supply rather than DC from a control unit it's worth also checking with a multimeter on a low AC volts range between earth and the iron tip that there isnt a AC voltage on the tip due to capacitive coupling from the element (which some irons meant for non-electronic use do suffer from and which is at least as dangerous to integrated circuits as static)

 

The landrover is really nice - my GS 35LK88 is also ex Ghurka but a bit more recent (1994 in service) - I intend to fit it out with a 320 and 352/TUUAM clip in installation once I get over the house move

 

Welcome to VMARS !

 

Regards

 

Iain

73 de G0OZS

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I put your name on the form!

 

Hope you don't mind, btw I have found a new logic module for the IBMU!

 

Only £4.99 so nothing to lose.

 

I don't want a cheap iron, needs to be something decent so don't mind spending, there seems to be some good ESD non Weller irons for around £50 on gleebay, will post link to see what you think.

 

With VMARS, thanks for the welcome but I don't have a c/s yet, for the last couple of years have just tuned to dummy load but need to move on, past life must be left behind, I'm not a radop or RSI any longer plus all the rest. I believe I must apply to OFCOM initially for c/s then take the RSGB exams. I tried to contact my local society in Melton but nobody bothered to come back to me, also tried Colin at Thorpe Camp but similar. On their site there are some contact numbers for others so will try them this week for exams.

 

Regards

 

Bob

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Bob

 

You need to find a radio club offering a course and exam for the Amateur Radio license and armed with the pass certificate you can apply to OFCOM for the license. There are now 3 levels - Foundation, Intermediate and Full - for Clansman kit the power and frequency coverage are such as to require an intermediate license which is the 2nd level.

 

The Radio Society of Great Britain website http://www.rsgb.org.uk has details of local clubs and their courses - I help with the ones at the Felixstowe club and I know our exam secretary would respond in a few days to any inquiry as we are always trying to get enough candidates to make the combined foundation course and exam viable so it's disappointing that you didn't hear back !

 

Best Regards

 

Iain

73 de G0OZS

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Hi Iain

 

There's one at RAF Waddington (one of my former stations) which is 35 miles away and I know is very well supported.

I will probably go there, its 'home' ground to me if you get my drift and my mate from the past life is stationed there too.

 

Thanks for the club finder, interesting there are no contact details for Thorpe Camp, I would like to have gone there as not been that way for years. We shall see. Shame Felixstowe is so far away.

 

Regards

 

Bob

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Have you looked at gas soldering irons?

 

Sorry but you've lost me, I'm talking about replacing capacitors on circuit boards and I cannot for the life of me see where a gas iron comes in unless I want to fry the board - or am I missing something ?

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Strange you should say that - I used to use a small one for the desoldering phase of surface mount repairs (in hot air gun mode). They are Ok for occasional use as a conventional iron as long as you remember to touch something earthed reasonably frequently to ensure that there is no static - I found that the catalyst bits have a relatively short life if used as a main soldering iron (so best to buy a bag of spares at the same time as the iron) and they are of course unregulated as to tip temperature so you need to be quick to avoid cooking things. For field repairs to cables and connectors they are ideal and mine has got me out of trouble loads of times

 

Iain

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Now for pics of the PSU card;

 

IBMU PSU card.jpg

 

The problem areas are as follows, C14 & C26 22uF 16V tants;

IBMU PSU card problem tants - C14, C26.jpg

 

C40 & C54 33uF 25V tants;

 

IBMU PSU card problem tants - C40 & C54.jpg

 

The limited info I have states that C11, C16, C20 & C38, all 22uF 40V tants are not normally a problem but "should be suspected if no output on the 12V rail" - not sure what this means as yet in respect of 12v rail and location. It suggests that these can be replaced with "normal electrolytic 125 degree C type in these positions. This would keep the cost to sensible proportions where low ESR would not seem to be prime requirement" - again not sure how this translates?? pics of these below, they are quite large and apparently expensive;

 

IBMU PSU card possible problem tants.jpg

 

IBMU PSU card possible problem tants_.jpg

 

Now the big question: Where my other IBMU powers up but reports low voltage, error code 1.31, vLO, does this fault lie within the PSU where a tant is reporting low voltage input even though the voltage input is proven correct, or does it possibly lie within the Logic module?

 

If I can identify this error code and its reporting source then it's cracked.

 

I will order the parts I need in the coming week.

 

Bob

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Strange you should say that - I used to use a small one for the desoldering phase of surface mount repairs (in hot air gun mode). They are Ok for occasional use as a conventional iron as long as you remember to touch something earthed reasonably frequently to ensure that there is no static - I found that the catalyst bits have a relatively short life if used as a main soldering iron (so best to buy a bag of spares at the same time as the iron) and they are of course unregulated as to tip temperature so you need to be quick to avoid cooking things. For field repairs to cables and connectors they are ideal and mine has got me out of trouble loads of times

 

Iain

 

I can understand its use in cable and connector repairs but would have thought not for pecs, I am aware of the use of the hot air gun for desoldering.

 

However, thanks to you all for your input, this is a steep learning curve for me and I don't mind admitting it :D

 

Bob

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Bob

 

Equivalent electrolytics of similar or slightly higher capacitance and voltage are relatively cheap - pennies not pounds - Tantalum caps were a premium device in their day.

 

I cant quite read the text printed on the PCB in the whole board photo but I expect that there will be test points for each output - the catch may be that a REME workshop or the base repair workshop would have had an extender card to allow a board to be raised out of the chassis for in-operation measurements to be made.

 

You should actually be able to get some signs of life by removing a suspect capacitor - their role is to filter noise and ripple on the supply output - if they fail short circuit they will stop a supply working but if they are removed there will be a noisy output which should at least give signs of life.

 

The capacitors aren't monitored directly - the VLo will be measured by the microprocessor board which will have an analogue to digital converter and some kind of electronic switch able to select various supply inputs and outputs for measurement - the one it is complaining about is likely being dragged down by component failure causing excess load.

 

I suspect on looking at the PSU board that it contains two white converter modules fed from the raw DC input - one will be generating a stable 24V (the longer one with readable text in the zoom photo) - I dont know what the other one is - if 5V it probably supplies the microprocessor if 12V it could be anything. You should be able to measure the output voltages of these converters to check some of the supplies as they have helpful voltage and pinout information printed on top - the challenge will be doing it safely with no extender card. Probably the best way is to tack temporary insulated wires to the pins underneath with solder and bring the ends out to a multimeter.

 

There also looks like being a discrete component voltage converter at the right hand end of the PSU board - this is probably rated for higher currents than the converters and I would guess that it provides the +30-something volts needed for constant current battery charging up to 28V - if you can provide a close up photo I may be able to guess more about how it works and suggest a safe test point.

 

Hope this helps

 

Iain

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Sorry but you've lost me, I'm talking about replacing capacitors on circuit boards and I cannot for the life of me see where a gas iron comes in unless I want to fry the board - or am I missing something ?

 

If you read this review you will see that it is a soldering iron not a mini gas torch that I'm suggesting (this particular gas soldering iron is out of production but the review gives general pointers on buying and using a gas soldering iron):-

 

http://www.epemag.wimborne.co.uk/gas-soldering-iron.htm

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The IBEK modules are still available btw: http://www.texim-europe.com/power-supplies/dc/dc/search#&&RadViewPageIndexState=0

 

Type IBEK in the search box for a list - the exact models in the IBMU may not be there but it at least means the vendor is still in business and it explains how to decode the part numbers - 24IPS3-1515 seems to be 24V nominal input 3 Watts 15-0-15V out - from what I can read in the photo the small one is a 15-0-15 supply (probably for the analogue circuits) and the longer one is a 5V logic supply - the discrete component supplies at the end of the board must be the high current 12V and charging supplies.

 

On the soldering topic I used to have a Weller Pyropen portable gas iron that had interchangeable soldering and hot air bits - the soldering version had a side exhaust for the hot gases and you needed to watch where it was pointing, but it was convenient for field repairs. See: http://uk.rs-online.com/web/p/soldering-irons/0660422/

Edited by g0ozs
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not sure if this works but file from widney ash attached

 

Hi David,

 

Many thanks for this, much appreciated. I had hoped it might identify the vLO alarm code "1.31" but unfortunately doesn't. Not to worry, its still very useful to have.

 

Do you have any other Widney IBMU info?

 

What we really need is the REME field repair manual.

 

Regards

 

Bob

Edited by Bob042
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Some more pics of the PSU board, right hand side as requested by Iain,

 

IBMU PSU card RH side.jpg

IBMU PSU card RH side_.jpg

 

Also close up of both IBEKs;

 

IBMU PSU card IBEK details.jpg

 

Next move back to the Analogue card and test pins as follows;

 

IBMU Analog card test pins.jpg

 

The pins are located top right of the card, the limited info I have states " The various voltages can be tested from the test pin points on the front of the Analogue Module. When working on the PSU card I normally power these individually from a current limited 24v laboratory power unit, this makes testing of the individual supply outposts much easier"

 

There are also 2 other pin points on the Analogue card, see below;

 

IBMU Analog card test pins_.jpg

 

IBMU Analog card test pins_1.jpg

 

Next the Logic Module, 2 test pins here;

 

IBMU Logic module test pins.jpg

 

Regards

 

Bob

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"When working on the PSU card I normally power these individually from a current limited 24v laboratory power unit, this makes testing of the individual supply outposts much easier".

 

This doesn't really make sense, but I assume it's trying to say that the PSU card can be powered up out of the rack from a bench supply to check that the various outputs are being correctly generated. Seems a good place to start.

 

Andy

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David

 

Thanks for the manual.

 

Bob

 

I guess with the unit reporting VLO from a good supply we are at the "backload for repair" stage now. The manual does confirm that it is sampling the input voltage (as it sees it) so it is probably worth tracing that with a voltmeter from the input connector into the unit to see if something has gone high resistance - I imagine the path will be something like socket > filter > fuse > switch or relay > PSU board IBEK inputs. In the past there have been issues with inductors in the input circuit of the 14V DCCU getting hot and going high resistance so that would be worth eliminating here.

 

The test pins are a good match to the 5 and +/-15V outputs of the IBEK units - I imagine when the unit is assembled and powered the PSU outputs can be measured there - I wonder if your source is trying to say "or an external supply can be connected there to replace a faulty PSU card?"

 

The clock and reset pins on the logic board likely allow you to reset the microprocessor (usually by momentarily grounding the reset pin) and determine whether the clock oscillator is running in cases where the display is dead, by checking for a squarewave at a few MHz on the clock pin using an oscilloscope

 

Hope this helps

 

Iain

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Hi Iain & everyone else following this,

 

I think what I'm going to do is get myself a small lab 30v DC psu with variable voltage setting to power the IBMU and test out from the pins on the analogue and see what I come up with, I don't want to be doing it in the back of the wagon for obvious reasons. I need to try and nail what this alarm code "1.31" means otherwise I will have to go down the route of changing all the tants as listed and hope that nails it, starting with the PSU card and testing each card as the suspect tants are replaced. One thing, I don't have to do the Logic mod as there is a replacement.

 

How would I test the cards out of the unit? I don't see the possibility of this as I don't have the expertise and experience.

 

Also outside of common sense electrical safety, anything special I should be thinking about? - equipment safety too of course.

 

Regards

 

Bob

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