For repair on the table today came a Lanzar Optidrive 11000.1d a big class d mono.
Some strange things I see:
1.
Switches on normal. No protection. But no output.
Just when turn up the input voltage the first time (I think to 500mV) there is suddenly output. No output relais in this amp. When it is oscillating it stays on normal, then I can turn down the volume to 0 and up again and it's working normal. Opampvoltage is ok at +/- 12V.
2.
Without load to maximum 130Vac unclipped outputsignal, seems ok. Idle current 4A.
With load of 2 ohms there is just 11,5Vac output (50Hz sinewave) at inputvoltage 12V and input current about 40A! Which tells me the total efficiency is about 15%...not good. 🙁
3.
There is 12V on the input RCA shielding.............meter between power ground en shield.
This amp uses two class d drivercards with each an old CD4070 and opamp. And in total 4x IR2113 mosfet drivers.
Servicemanual I cannot find, maybe there are other brands which uses the same circuitry?
Any other info is welcome, thanks...
Some strange things I see:
1.
Switches on normal. No protection. But no output.
Just when turn up the input voltage the first time (I think to 500mV) there is suddenly output. No output relais in this amp. When it is oscillating it stays on normal, then I can turn down the volume to 0 and up again and it's working normal. Opampvoltage is ok at +/- 12V.
2.
Without load to maximum 130Vac unclipped outputsignal, seems ok. Idle current 4A.
With load of 2 ohms there is just 11,5Vac output (50Hz sinewave) at inputvoltage 12V and input current about 40A! Which tells me the total efficiency is about 15%...not good. 🙁
3.
There is 12V on the input RCA shielding.............meter between power ground en shield.
This amp uses two class d drivercards with each an old CD4070 and opamp. And in total 4x IR2113 mosfet drivers.
Servicemanual I cannot find, maybe there are other brands which uses the same circuitry?
Any other info is welcome, thanks...
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Have you contacted Lanzar? They will send you some diagrams.
What's the resistance between the B+ terminal and the RCA shields?
What's the resistance between the B+ terminal and the RCA shields?
With the amp switched off for many hours, caps are empty..:
B+ <-> RCA shield = 215 ohm fixed
power ground <-> RCA shield = 1 kOhm about, but I think there are some capacitors influencing this value.
B+ <-> RCA shield = 215 ohm fixed
power ground <-> RCA shield = 1 kOhm about, but I think there are some capacitors influencing this value.
If there is a 220 ohm resistor near the RCA jacks, you probably have a primary to secondary short in one of the transformers. If twisting/pushing/pulling on one specific transformer changes the reading significantly, that's likely the defective transformer. The short generally occurs where the terminal winding meets the rest of the windings.
Yes spot on, one transformer is making these 220 ohm connection. When flipping over the amp the value varies between 2k2 and 215 ohm...twisting one of the four transformers it varies also.
I'm get out the boards of the heatsink and see if i can repair it, thanks!
I'm get out the boards of the heatsink and see if i can repair it, thanks!
I have to test again after removal and replacing the transformer, it looked ok.
But other things to do with higher priorities.
But other things to do with higher priorities.
Continued with this amp...
Resistance between B+ and RCA is about 1,5k Ohm now.
After removing en checked one power supply transformer I tested the power supply separated from the class d section. Output seems to be normal, +/-30V low power and railvoltage about +/-105V wihout load.
With the class d board connected it goes direct in protection. Mosfets are all ok, driver IC are 4x IRS2113 dip14. Maybe the protection circuit itself, but without diagram it takes a really long time to find the cause.
I contacted Lanzar - Pyle but they refused me to send the diagrams. Any info is welcome, amp is rather new but useless now...
Resistance between B+ and RCA is about 1,5k Ohm now.
After removing en checked one power supply transformer I tested the power supply separated from the class d section. Output seems to be normal, +/-30V low power and railvoltage about +/-105V wihout load.
With the class d board connected it goes direct in protection. Mosfets are all ok, driver IC are 4x IRS2113 dip14. Maybe the protection circuit itself, but without diagram it takes a really long time to find the cause.
I contacted Lanzar - Pyle but they refused me to send the diagrams. Any info is welcome, amp is rather new but useless now...
I think the design is likely the same, the output section of the 11000 has more output mosfets as far as I see, thanks a lot.
When switching on, it goes direct in protection. It pulls about 0,5-1A peak maximum.
When switching on, it goes direct in protection. It pulls about 0,5-1A peak maximum.
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