Second Macrotech 5000VZ repaired
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Topic: Second Macrotech 5000VZ repaired
Posted By: DjLeco
Subject: Second Macrotech 5000VZ repaired
Date Posted: 24 January 2012 at 6:24pm
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Channel 2 had blown outpud devices, I have replaced all with new ones, On Semiconductor , recalibrated bias and testing.
Enjoy it in mine poor speaked english
 , and excuse when I said eicht ohms, both dummy loads are 4 ohms.INTRO: Presentation
http://www.youtube.com/watch?v=NUqhmonUG5o&feature=youtu.be" rel="nofollow - http://www.youtube.com/watch?v=NUqhmoNUG5o&feature=youtu.be
PART 1
http://www.youtube.com/watch?v=NNa_DQj5lv4&feature=youtu.be" rel="nofollow - http://www.youtube.com/watch?v=NNa_DQj5lv4&feature=youtu.be
PART 2
http://www.youtube.com/watch?v=SkUUTuDl61Y&feature=youtu.be" rel="nofollow - http://www.youtube.com/watch?v=SkUUTuDl61Y&feature=youtu.be
LAST PART
http://www.youtube.com/watch?v=D0gknrSTxLY&feature=youtu.be" rel="nofollow - http://www.youtube.com/watch?v=D0gknrSTxLY&feature=youtu.be
------------- I'm A Stupid SMART Romanian... |
Replies:
Posted By: kedwardsleisure
Date Posted: 24 January 2012 at 6:26pm
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Did you use genuine Crown transistors ------------- Kevin North Staffordshire |
Posted By: M4trix
Date Posted: 24 January 2012 at 6:33pm
Probably he used MJ15024/25 but if he matched them by the VBE I don't see any problems. |
kedwardsleisure wrote:Posted By: kedwardsleisure
Date Posted: 24 January 2012 at 6:53pm
|
Expensive way of doing it though as they are matched both by Vbe and Hfe. Wonder how many boxes you need to get enough for 1 amp. Macrotechs need the same 'grades' on both channels since they are designed to run in parallel mono as an option which means equal current sharing on L&R channels. ------------- Kevin North Staffordshire |
Posted By: DjLeco
Date Posted: 24 January 2012 at 7:35pm
I used MJ21195+MJ21196, SOA 3A/80V  ,matched 10%, selected from 50 pairs, buyed from Mouser,for fixing faulty CH2.
http://www.onsemi.com/pub_link/Collateral/MJ21195-D.PDF" rel="nofollow - http://www.onsemi.com/pub_link/Collateral/MJ21195-D.PDF
The other channel has been repaired by other electronist, and it have a "mixture" of C8187 and C8188 originals crown (motorola's OEM for Crown output devices), and MJ15022+MJ15023 and MJ15024+MJ15025, wich shows me, CH 1 was repaired more than 2 times, regarding date and code of output devices...
Also one curiosity of me, was I found blown 8 output devices (4 PNP and 4NPN shortcircuited) from 8 pairs on both sides of groundbridge output topology, and from them, most part was Crowns marked output devices (3 pairs), and just one pair of MJ15024-MJ15025, also that channel was fixed minimum one time (mixed output devices, Crown+On Semi...
So, from here I can realise 2 options:
Used OLDER silicon on Crown output devices,(marked W97 40 wich tells me year 1997, week 40, date of manufacturing) ,aging due to many cycles of heating cooling or lower beta of On semi devices...
I told to the owner, when he makes some money, to come and replace all output devices too, on CH 1 for maximum safety.
Also, the amp will run exclusive on stereo mode, loaded 2,66 ohms (3 subs) per channel. ------------- I'm A Stupid SMART Romanian... |
Posted By: kedwardsleisure
Date Posted: 24 January 2012 at 9:46pm
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I have seen many macrotechs (of all sizes) fail after previous repair with non crown graded outputs. Ditto, Peavey which also have some selected IC's. , MC2 and C-Audio to name a few more. Since load hogging or shedding across the load range is no doubt the cause of failure in such cases, it can either be the new ones or old ones that fail. I always fit original crown transistors. Most types are only available in 2 grades now which makes it interesting! Good video Claudiu and I hope you didn't set fire to your lovely parquet flooring with those resistors! English accent good too  ------------- Kevin North Staffordshire |
Posted By: DjLeco
Date Posted: 24 January 2012 at 10:29pm
Floor are ceramic tiles (1,2 cm thickness) not wood parquet! 
Ch 1, wich was repaired couple years ago ( I spoke to the owner, he told me it was repaired 2 years ago), didn't failed, with mixture of non Crown output devices, 3 kind of...
I bet as Ch 1 of the amplifier, the difference between the final transistors is much worse than the fixed channel of me ...
Will see how many time, mine fixing will work...  ------------- I'm A Stupid SMART Romanian... |
Posted By: Elliot Thompson
Date Posted: 24 January 2012 at 11:35pm
Congratulations! Best Regards, ------------- Elliot Thompson |
Posted By: DjLeco
Date Posted: 25 January 2012 at 7:58am
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Thank you for your appreciation, Mr Thompson.
U used english spoken, for all possible next fixers, to understand how it works VZ supply of Macrotech's VZ series amps, also how must show sinusoide on output.
The only trouuble was I cannot feed the amp with exactly 230 volts, wich he was presteted.
Couple watts was lost, officially must have around 91-92 Volts rms clean on output, for 230 volts main... ------------- I'm A Stupid SMART Romanian... |
Posted By: Earplug
Date Posted: 25 January 2012 at 4:32pm
I must admit I´ve replaced the originals with MJL´s in a couple of Macro and Microtechs, but (so far) not had them come back again! If I find blown o/p devices, I will (generally) just change the lot as it´s a safer. Maybe that´s what saved me with those. And what´s that about 2 grades of o/p transistors for the Crown amps? Please explain.  Thanks. ------------- Earplugs Are For Wimps! |
Posted By: Elliot Thompson
Date Posted: 25 January 2012 at 9:01pm
The difference between 89.5 volts (2002.5 watts) versus 92 volts (2116 watts) @ 4 ohms is a mere +0.23 dB! The Crown Macrotech 5000vz service manual states the amplifier must meet the minimum of 89.4 volts in a 4-ohm load, with no more than 0.05% (Before clipping) THD. So your tests proves the amplifier is delivering the proper power as if it was repaired at Crown's facilities.  Best Regards, ------------- Elliot Thompson |
Posted By: Tarkovsky
Date Posted: 25 January 2012 at 10:04pm
| I have no idea how any of this repairing business works, but good job! |
Posted By: kedwardsleisure
Date Posted: 25 January 2012 at 10:55pm
Crown used to grade the motorola transistors into groups, and inkstamp a little number on them. Grade 0,1,2,3,4 according to similar Vbe and hFE. So an amp would have all PNP of one grade and all NPN of another (or the same) grade throughout L&R channels. This is to ensure correct current load share tracking throughout the load on the amp, whether in stereo or parallel mono, in idle or full power, Hi-VZ or Lo-VZ, hot or cold. In parallel mono, you can physically connect the L&R channels together for low impedance loads but then the L&R channels must equally load-share of course. Nowadays they use a small coloured paint mark eg black, red, green etc which means the same thing, with or without the original crown house part number. Maybe ON semi (successor to Motorola) are making the transistors more consistently now; I dont know, but you can now only get the transistors in the 2 grades, they've discontinued the others. These graded parts are used in most of the Crown-designed amps. Some grade-3 transistors  ------------- Kevin North Staffordshire |
Posted By: DjLeco
Date Posted: 26 January 2012 at 12:17am
At service center, are same people like us, "home fixers", but maybe with better and expensive measurements equippement...
Now, depends about the knowledge of each of us, and alot of other things, small but important ones...
Someones makes good job, checking on the smallest details, of bias, limmiter,offset, ODEP circuits,and a good job will result (if good components are used),
others are just replace JUST the blown output devices, without any kind of measurements , thinking fixing an amp is a joke...Bad results will occur earlier or later.
EDIT: nice and clean pic mr, kewardleisure
LATER EDIT: for those who want's to see, entire collection of amp's that I have fixed and tested, be my guest here, where I'm moderator at amp section!
http://www.forum.poweraudio.ro/viewforum.php?f=64&sid=e10e24956561623d7e067473c7044679" rel="nofollow - http://www.forum.poweraudio.ro/viewforum.php?f=64&sid=e10e24956561623d7e067473c7044679
Is in Romanian language, but pictures and youtube tests, can be seen (accessed) without log in (without user account), so, be welcome all of you!
------------- I'm A Stupid SMART Romanian... |
Posted By: jens__m
Date Posted: 16 July 2012 at 12:23pm
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Hi, I am repairing a Macrotech 5000VZ that has the following symptoms: No light in the ODEP led Constant light in the Signal / IOC led I have changed all the output devices and some pre drivers (Q511, Q512, Q525, Q526) and checked a lot of other components. I found a resistor that was burned (R543, 22R Flame Proof) but changing this didn't make the amp work. The powersupply is in stand-by for this channel, so i can't make any adjustments. What can cause the channel to go into standby immidiatly? Any ideas apprecheated Thanks in advance |
Posted By: kedwardsleisure
Date Posted: 16 July 2012 at 11:54pm
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sounds obvious but there must be another component or two still faulty you've not found yet. While the amp powers up, check for any DC offset on the terminals. The IOC light will not go out and ODEP will not come on if the offset is out of spec while the amp soft starts. As it's a 5000, you can at least swap over the output transistor cassettes to prove if the fault is there or elsewhere. Bad blow-ups can travel from the output to the main pcb. I assume you've checked the fuse as well  ------------- Kevin North Staffordshire |
Posted By: jens__m
Date Posted: 17 July 2012 at 7:30am
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Hi, I have tried to take the other output transistor cassette and replace it with the one that i repaired. Then the channel works perfectly, and the other channel won't start. The failure has to be in the repaired output module! I'll check for DC offset during startup and on the faulty channel i got max. 200mV DC. The working channel peaked at 2.8V DC. If i measure the power supply voltage, i only get a couple of volts on the faulty channel, and about 90V on the working channel. Is there any components that is used to start-up the PSU? |
Posted By: DjLeco
Date Posted: 17 July 2012 at 8:19am
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First check to have all VZ ODEP swithers on VZ odep mode.
http://postimage.org/image/5wrr1cp3j/" rel="nofollow">
 Check both power supply of amp with good output channel module (the working one transistor cassete) for +/- 86-94Vdc depending of mains soket variations, officialy is +/- 90Vdc, if ok, measure between collectors of output devices (mains heatsinks, +VCC Buss Bar and -Vcc Buss Bar) to have also 90Vdc, if is more, around 170-180Vdc, you have shortcircuited mosfets on VZ power supply (Q810,811,812 respectively Q800,801,802 for other channel).
Also if you find blown mosfets, replace too the 555 timers U703, and (or) U709, and Q710 and (or) Q711 transistors.
You can also test the VZ is working, simply loadind the amp with 8 ohms, amd measuring between +Vcc Buss Bar and -Vcc Buss Bar of tested chennel, in idle voltage is around 90Vdc and increasing output level will increase too, the tension between +Vcc Buss Bar and -Vcc Buss Bar , more than 125-135Vdc, but assure the VZ switch is set on VZ ODEP position.
If all measurements shows around 90 volts, and raise same time with increasing output power on 8 ohms load,looks the VZ power supply stage is working ok.
On faulty Channel, check if the fault led E102 or E202 is lighting.
When that led is lighting, that cassete with output transistors, have shorted output devices, wich acts for releasing contacts of mains primary power relais K700 and K701, for open circuit, and all mains supply tension will fall on positor thermistor (PTC) R702 and R732, making protection to work, avoiding chain reaction distruction.
R702 and R732, are PTC (positive coeficient temperature thermistor), wich his resistance will increase same time with temperature.
Take care, those PTC,s must have working tension of 265 volts, are specially designed for innrush current limmiter on soft start circuit, and if protection has been activate (blown output devices shorted), on his terminals you will measure entire mains supply (220-240 Vac).
Schematics and service manual, can be downloaded from here:
http://www.crownaudio.com/legacamp.htm" rel="nofollow - http://www.crownaudio.com/legacamp.htm
Good luck! ------------- I'm A Stupid SMART Romanian... |
Posted By: service dept Steve
Date Posted: 17 July 2012 at 12:21pm
You are being lead the wrong direction. The control board will not allow the amp to switch on in fault mode so don't worry about trying to measure power supply voltages or offset voltages as there aren't any! What you have done so far is correct, when the modules are swapped the fault goes with the module. Carefully check and then check again the work you have done so far, it is possible to get the modules in wrong way up, obviously it is also easy to get the wrong transistors in the heatsink, especially if they have all been out of the module. The check is that the two modules when side to side in the frame will not have the same devices in them nor will they look the same, if they do then that's is wrong. Once you have established that the correct parts are in the correct modules and they are the right way up then part both modules and swap the (marked up) boards over, if everything is in the right place then one module will work and the other not, this will tell you which circuit board the fault is on. Let us know how you get on. ------------- We are not "They", We are "The others" http://www.servicedept.co.uk" rel="nofollow - http://www.servicedept.co.uk - |
Posted By: kedwardsleisure
Date Posted: 17 July 2012 at 9:00pm
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The amp will attempt to power-up the channel via the soft start triacs, whether or not there is a DC offset...it has to, otherwise it won't know there's a dc offset. That is the buzzing sound. If the offset exceeds the threshold, it switches off again and has another go after 4 seconds if the offset has disappeared. This offset can be measured at the speaker terminals (there's no speaker relays on a 5000). Only when all protections are negative will it complete the soft start ramp and close the power relays. That is why a 5000 goes brrrrrr.........click-click when it's happy. The soft start is a constant-current-limited operation where the charging is kept to a safe level. ------------- Kevin North Staffordshire |
Posted By: service dept Steve
Date Posted: 17 July 2012 at 11:14pm
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Agreed, that is how the dc detector works, it also lights a led on the main board which may offer a clue, Dc faults on a grounded bridge amp are much less common than on a conventional design but there are several other faults that the controller will not allow the amp to try to start under, namely over or under voltage and (almost certainly the case in this case) over current.
------------- We are not "They", We are "The others" http://www.servicedept.co.uk" rel="nofollow - http://www.servicedept.co.uk - |
Posted By: kedwardsleisure
Date Posted: 17 July 2012 at 11:25pm
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------------- Kevin North Staffordshire |
Posted By: jens__m
Date Posted: 18 July 2012 at 11:01am
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The problem was that i had mounted the output devices wrong... doooh!! (PNP instead of NPN and reverse) Damn replacement transistors...After mounting them correctly every thing worked perfectly, and adjustments could be made. Best regards Jens Mortensen
|
Posted By: service dept Steve
Date Posted: 18 July 2012 at 1:16pm
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What is referred to as a "kick self" The offset would have been 0.7v and the position of the vz lock switch would have been totally immaterial. ------------- We are not "They", We are "The others" http://www.servicedept.co.uk" rel="nofollow - http://www.servicedept.co.uk - |
Posted By: kedwardsleisure
Date Posted: 19 July 2012 at 12:13am
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lucky ------------- Kevin North Staffordshire |
Posted By: ceharden
Date Posted: 19 July 2012 at 12:58am
| In my experience (limited, I'd like to stress!), putting the output devices in the wrong sides of the module ends up with the magic smoke being released needing a new set of output devices. |
Posted By: Tan-2
Date Posted: 01 July 2013 at 2:04pm
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Greetings to all, I've just been lumped with a 5000vz that powers up then protect and try's to start again.. will do some o/p check's for s/c and look about the psu. All the above comment's are useful to get this under way.. Regards A. ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: DjLeco
Date Posted: 02 July 2013 at 8:37am
Check on main board, you have some diagnostic leds (red ones marked by me), and tell wich stays lighted after power it on.
http://postimg.org/image/8w4lcpedr/" rel="nofollow">
 If DC/LF led stays on, you have Offset DC on output, possible one transistor from quadrant output be failed.
If Fault led stays on, you have shorted output devices on that channel.
------------- I'm A Stupid SMART Romanian... |
Posted By: Tan-2
Date Posted: 02 July 2013 at 9:28am
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Thanks for reply, I will be working on amplifier tomorrow and check marked led's for fault indication. Also on rear speaker out put panel it was missing it's red and black cover's just showing bare screw connector's so this made me think that it's out o/p's had been shorted out via speaker connection's. Regards for now. ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: Tan-2
Date Posted: 03 July 2013 at 11:53am
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On checking so far I've found soft start circuit in rush limiters both open circuit also repanel speaker protection switched off on both channels.. More checking to be carried out. Regards A ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: Tan-2
Date Posted: 08 August 2013 at 10:50pm
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More comments with this repair.. after contacting ems electronic music service regarding spare's for the pth thermistor, they said yes we carry spares for this amp and the old gray disc is now a blue one but smaller? so after ordering two of these...followed by a few days wait, now on opening the pack not only did they look half the size but I was thinking how can this hold the inrush with out going pop?.. I've also had to order a large chassis socket and fit it to it's own wall supply so not to tip the circuit fuse plus I will be ramming it up with my trusty viariac or just power on and let it do it's self checking plus watch the fail safe leds in the rear pcb. more notes to be added. ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: Tan-2
Date Posted: 08 August 2013 at 10:54pm
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Just to add, ems charged £15 qid for the thermistors s/h...rs components do the same blue one's for under £4..!! so back to rs...it pays to check about. ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: kedwardsleisure
Date Posted: 09 August 2013 at 6:51pm
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the 5000 has full phase angle controlled soft start so shouldn't trip any breakers unless you're plugged into a lamp socket 50's style. ------------- Kevin North Staffordshire |
Posted By: DjLeco
Date Posted: 09 August 2013 at 6:54pm
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Also keep in mind that is an 265 volts/6,8 ohms/10 amps PTC thermistor! ------------- I'm A Stupid SMART Romanian... |
Posted By: Tan-2
Date Posted: 09 August 2013 at 8:37pm
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I've ordered some 10amp @6ohm..
------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: kedwardsleisure
Date Posted: 09 August 2013 at 9:11pm
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the small blue ones superseded the older thick grey ones, Crown fitted them on later revisions. ------------- Kevin North Staffordshire |
Posted By: Tan-2
Date Posted: 09 August 2013 at 9:20pm
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thanks for the fast reply, tho the blue one's looked a little thin and as a temp replacement to check the unit I pre-fitted 6 ohm 50 watt and powered up the amp then powered down as it was getting late to keep at it. ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: DjLeco
Date Posted: 10 August 2013 at 10:19am
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That thermistor is PTC, positive coeficient temperature, wich means his internal resistance increase same time with increasing current within.
In fault case on that thermistor , entire voltage supply of soket (110 or 220 volts), will fall into it, and being in protection mode, that relais that shunts softstart section (triac+PTC), will stay OPEN CIRCUIT, in fault mode.
So that PTC thermistor will have maximum internal resistance, and current in primary trafo will be almost 0.
So that's why U can't use 6,8 ohm resistor, even at 100 watts, it will blew instantly if that channel of amp is FAULTY, with shorted output devices, or rectifier bridge!
If you replace that thermistor with NTC thermistor or shunted directly, in fault mode, you will explode SoftStart Triac, when powering on the amp!
Very smart type of protection implemented by Crown, same is on XTI series 1000-4000 (just thermistor).
So U can order those PTC thermistor from Crown for XTI series, is exactly 6 Ohms/265 volts/10 amps, and is BLUE! ------------- I'm A Stupid SMART Romanian... |
Posted By: Tan-2
Date Posted: 13 August 2013 at 3:42pm
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After checking out put modules both have a odd reading! The npn 2sc4929 from base to emitter reads 70 ohm yet the one next to it reads 130 ohm plus both out of circuit are ok. Even the to-3 are all fine no s/c there both blocks are the same no s/c o/ps... Mined you it needs a dam good clean up., so it would back to psu for checking.., Or maybe the ptc just failed but the triac is ok no short circuit there.. ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: Tan-2
Date Posted: 13 August 2013 at 9:41pm
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So after going through both modules all is fine next psu circuits to be checked. ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: Tan-2
Date Posted: 20 August 2013 at 12:26pm
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After spending most of the day rechecking both channels for s/c all devices are ok no s/c there.. also power fets are in good order. Now replacement of ptc thermistors, triac's are good next power up but then a pop sound so shut chassis down and drained caps. next step will be to check voltages off load to see if there working. need to get this amp back on track. suggestion's welcomed.... ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: Tan-2
Date Posted: 22 August 2013 at 6:20pm
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More odd finding's with this repair.. now, the rear connection flat plated connector from power amp module to speaker o/p board is a little weird. It's giving a reading of 70 ohms! now if you remove both ends and take a reading across the speaker o/p board you get 1731 ohms and if you re solder one end and don't connect the remaining end to the the power amp module you get 70 ohms?? so I just used the second connector to prove a point, so there appears to be a faulty connector as there should not be any ohmage reading with both ends open. Why use such a thin connector cable on such a powerful amp? More to do with this amplifier as there's different readings between each o/p and ground to both channels.. (faulty) side 1047 ohms and 1780 ohms on the good channel. ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: Tan-2
Date Posted: 03 September 2013 at 8:40pm
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more going's on with this amplifier...after checking between o/p modules there is slight difference in metering also the heavy grade cooper link cable has a problem...with it removed, it reads 70 ohm plus it's other cooper cable reads normal when removed from the amplifier with both ends o/c.. I did not have spare cooper link cable so used heavy duty cable that will handle that type of current.. one more thing here it's wiring colour code is white black.. so the black wire would be live and white would be neutral..someone did say it way was the other way?? so rechecked american wire code and it says black live.... I'm now thinking due to that cable heating up and breaking down that's why the amp failed,,, ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: kedwardsleisure
Date Posted: 04 September 2013 at 11:56pm
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there is an official mod from crown to fit fibreglass sleeving over the printed conductor to stop it rubbing and shorting on the case. ------------- Kevin North Staffordshire |
Posted By: Tan-2
Date Posted: 05 September 2013 at 4:17pm
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Thanks for reply, I've removed both cooper cables and fitted heavy duty wire that will handle the current of amplifier... to recap.. I've checked all o/ps/ driver's/pre-drivers to both blocks and there is no short circuit found.. plus have checked b-diodes /fet's to it's psu..triac's are ok....next will be on power to see if all is ok. more to do....it's an epic amplifier to work on.. ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: Tan-2
Date Posted: 16 September 2013 at 4:41pm
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So after a break from this amplifier it was back to it...power up time, first go no front panel LED near on off switch but a quick recheck on connections and then power up all good so far next will be load testing and see how things go. ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: Tan-2
Date Posted: 16 September 2013 at 4:43pm
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The main fault was the rear speaker cooper cable plus soft start circuit ptc's .. ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: Tan-2
Date Posted: 17 September 2013 at 8:34pm
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Hopefully this week I'll be carrying out load and soak testing to ensure all is well... ------------- Logic will get you from A to B. Imagination will take you everywhere. |
Posted By: Tan-2
Date Posted: 18 September 2013 at 2:19pm
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Systems all go.. Both channels running healthy.. Job done. ------------- Logic will get you from A to B. Imagination will take you everywhere. |