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T.amp TSA 4-1300 Power Amplifier Issue: Not Turning On, Red Diode Flashing, No Visible Damage

Matek920605 82899 348
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Why won’t the TSA 4-1300 power amplifier start, with the red board LED flashing and no obvious burn marks?

Most likely the flashing red LED means the small step-down supply is going into overload/restart because something in the inverter/output section is shorted [#18372738] In this model the usual root cause is blown primary-side IGBTs/IRGP4066D; one user found them “literally fired” [#18265750], and another explained that the SG3525 PWM drives the IR2110 gate drivers, which then drive those IGBTs [#18265973] Reported damaged parts in successful repairs included the IGBT pair, IR2110S drivers, SG3525A, 47Ω gate resistors, 1N4148 gate diodes, 15V zeners, and sometimes the GBU2506SF bridge/triac [#18505704][#21080060] A good diagnosis path is to check the output transistors for shorts first, then inspect the whole gate-driver and rectifier network before applying power again [#18265750][#18505704]
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  • #31 18277808
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    I am sending, only IR2100S, IRGP etc. are removed
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  • #32 18277898
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    I would like to add that after removing all damaged elements, i.e. {IR2100S x2, IRGP x4, rectifiers} - one ss heat sink
    one complete channel, I went through all the diodes marked EF8, resistors, capacitors, literally everything that is on the board - this time it turns out that everything else is working, i.e. capacitors, "EF8" diodes, etc.
  • #33 18278464
    INtRO_Tech
    Level 14  
    Posts: 194
    Rate: 6
    Hello, and the smaller T4 and T5 diodes with resistors are you also working? It's about this set at the output of the IR2110S, where there is key control (two sets per transistor from one IR), check, because I have lost resistors with diodes at this point.

    I was also looking for IGBT4066D equivalents and it is difficult to choose something cheaper ...

    Regards
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  • #34 18279020
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    With these t4 diodes and these resistors, most of them, when checked with a diode meter, showed a value of about 500, on some it did not show anything, but there is also no puncture.
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  • #35 18279725
    Anonymous
    Level 1  
  • #36 18279744
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    U9 chip: 72POZEAG3

    Added after 30 [minutes]:

    There is a rectifier bridge under the small heat sink
  • #37 18280283
    Anonymous
    Level 1  
  • #38 18280781
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    Yes, it is, these components are working
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  • #39 18280922
    Anonymous
    Level 1  
  • #40 18281247
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    EF8 diodes are all functional, only the smaller ones marked T4 and H5 are damaged, about 8-9 pieces in total show very low values or are punctured.

    Added after 2 [minutes]:

    There are a lot of these small "T4" diodes on the entire board, but only those that are connected to the IRGP, ir2100s are damaged

    Added after 3 [hours] 36 [minutes]:

    I am still wondering about the element marked on the board as "L10". The tester shows it as a 77.6 ohm resistor, but the meter is a breakdown

    Added after 1 [hours] 41 [minutes]:

    Schottky diodes are the ones marked T4 and H5.
  • #41 18283025
    Anonymous
    Level 1  
  • #42 18283286
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    I found a table with the markings of smd diodes, housing types, etc., the designation H5 sod123 is supposed to be 15v

    Added after 3 [minutes]:

    H5 sod-123
    Attachments:
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  • #43 18283332
    Anonymous
    Level 1  
  • #44 18283452
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    There is also a diode t4 and h5 in the vicinity of this "L10" coil, both of them are operational. There are quite a lot of these LEDs across the board
  • #45 18283657
    Anonymous
    Level 1  
  • #46 18283695
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    D212 - this is the T4 diode
  • #47 18283722
    Anonymous
    Level 1  
  • #48 18283969
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    D752 - here, for example, is the H5 diode
  • #49 18285925
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    The TRIAK under that little heatsink where the bridge rectifiers are is BTA41-600B, 600v 40A. I checked with the tester and it is damaged, however
  • #50 18285996
    INtRO_Tech
    Level 14  
    Posts: 194
    Rate: 6
    Hello,

    Desolder the triac to check, in the motherboard it shows as if it had a short circuit. I was the same.
  • #51 18286180
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    Well, I checked it under the tester, which was desoldered, it shows a resistor instead of the triac
  • #52 18357246
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    Hello
    I just received the last parts of the amplifier. The amplifier is assembled, I fired it, luckily nothing exploded, nothing was burnt. However, the fans do not start and the LEDs on the front panel were barely lit at first, and then they began to go out slowly. it seems to me that it is the fault of the rectifier bridges, measuring them earlier as if everything was fine
  • #53 18357872
    398216 Usunięty
    Level 43  
    Posts: 34022
    Help: 3914
    Rate: 9194
    Matek920605 wrote:
    I think it's the fault of the rectifier bridges
    You're right - you think ...
  • #54 18358096
    Anonymous
    Level 1  
  • #55 18359181
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    SG3525 generator replaced, drivers also. Exactly it turns out that the main converter did not start. When turning on the equipment, practically nothing happens, only the first time the LEDs were turned on, they lit up after some time and slowly faded out. You couldn't hear the typical switching. The IRGP transistors were warm.
  • #56 18362530
    INtRO_Tech
    Level 14  
    Posts: 194
    Rate: 6
    It will not bring anything to the topic, it will only be a curiosity - the "original" of this amplifier is the Leicozic DP41200 from China. I was terribly surprised by the places for potentiometers and the functioning clip / signal diodes covered with a heat-shrink, and the general guerrilla warfare inside.

    Regards
  • #57 18363248
    Matek920605
    Level 10  
    Posts: 54
    Rate: 12
    I reviewed the replaced elements again, I corrected February on Ir2110s (one pin was not prepared. I put everything together and turned on. This time after about 4 seconds you can hear the transformer turning on, the LEDs on the front panel do not turn on. Waiting a few seconds, the LEDs shown below on the motherboard they turn off, the transformer is no longer audible, after about 2-3 seconds the diodes light up again and you hear that the transformer is also working, but after a while it turns off again and again. Nothing heats up, nothing fires.
    Attachments:
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  • #58 18363399
    Anonymous
    Level 1  
  • #59 18364408
    Michel424
    Level 14  
    Posts: 203
    Help: 1
    Rate: 13
    Reading the topic, I wonder if it is sometimes better to change the power supply of this power amplifier completely, i.e. to make converters from scratch using parts from this converter? Generally, a lot of people have a problem with these tips and while the tips themselves rarely fail, their power supply is the biggest problem A and there are no diagrams to cover everything A pity because the end is quite popular due to the price and power
  • #60 18364932
    INtRO_Tech
    Level 14  
    Posts: 194
    Rate: 6
    I was also thinking about it, but you would need a very powerful converter to power this end, the modification with a transformer is completely out of the question due to the weight and size.

    All in all, only a part of the "HOT" power supply, i.e. the 230V side, would be to be made, only two pins per winding go to the transformer.

    Regards

Topic summary

✨ The T.amp TSA 4-1300 power amplifier exhibits a failure to power on, with a flashing red diode near the capacitors and no visible physical damage. Investigation revealed multiple damaged IRGP4066D IGBT transistors on the primary side inverter, along with damaged power transistors (NJW0302GC), MOSFETs (GP105N15M), rectifier bridges (GBJ3006SF, 2506SF), and driver ICs (IR2110S, SG3525A). The amplifier uses a full-bridge power supply topology operating around 85-100 kHz with multiple symmetrical voltage rails (+/-15V, +/-40V, +/-60V, +/-90V, +/-160V) for preamplifier and power amplifier stages. The power supply design lacks galvanic isolation, current limiting, and effective overload protection, leading to frequent IGBT and associated component failures. SMD components such as EF8 and T4/H5 diodes (likely Schottky and Zener types) near the inverter and driver circuits are critical and often damaged. The triac (BTA41-600B) controlling AC mains to the rectifier bridge is also a common failure point. Repair attempts require replacing IGBTs, driver ICs, rectifiers, and passive components, but without a schematic or service manual, troubleshooting is challenging. Oscilloscope measurements of PWM signals and gate drive waveforms are essential for diagnosing dead time and control issues. Some users suggest replacing the entire power supply with a custom design due to the amplifier’s complex and failure-prone power stage. The amplifier chassis serves as a ground connection, which must be properly connected during bench testing. Auxiliary power supplies (e.g., 2x12V AC transformers) are used to test amplifier channels independently. Despite extensive repairs, issues such as persistent fault LEDs, relay non-activation, and channel-specific transistor failures remain common. The amplifier is considered difficult to service due to integrated power and control boards, lack of documentation, and complex SMD circuitry. The original design is reportedly based on the Chinese Leicozic DP41200 amplifier. Community consensus highlights the need for careful component verification, replacement of damaged SMD diodes and resistors, and cautious startup procedures using current-limited power supplies or light bulbs to prevent repeated damage.
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FAQ

TL;DR: Field tests show idle draw ≈ 70 W and IGBT blow-ups can occur < 5 s after power-up if a channel shorts[Elektroda, Q-mac, post #18986130][Elektroda, Matek920605, post #18378061]; “this design is a ‘ticking bomb’”[Elektroda, aaanteka, post #18433299]—yet 90 % of outages come from six gate-drive parts.

Why it matters: fix those parts or add fuses and the TSA 4-1300/700 runs stably at reduced load.

Quick Facts

• Main rails: P ±30 V, H1 ±62 V, H2 ±125 V, H3 ±188 V DC[Elektroda, ziro_9, post #18380143] • Converter frequency: 70–85 kHz (SG3525-driven)[Elektroda, majccco, post #18700835] • Factory breaker: 24 A, rear panel; soft-start absent[Elektroda, INtRO_Tech, post #20627975] • Typical spare-parts bill: PLN 250–300 (≈ €55)[Elektroda, popej, post #18638050] • Idle power: 70 W @ 230 V; start-up surge ≈ 600 W[Elektroda, Q-mac, post #18986130]

Which components fail most often?

Statistics from 40+ repairs show the same six parts burn first: 1 × SG3525 PWM IC, 2 × IR2110S drivers, 2 × IGBTs (IRGP4066D-E), and 1 × BTA41-600 triac[Elektroda, Robercikxxx, post #20210106] Replacing them plus the 47 Ω gate resistors cures > 90 % of dead units.

What rail voltages should I measure on a healthy board?

With 230 V AC applied you need: P0 ≈ ±30 V, H1 ≈ ±59–62 V, H2 ≈ ±118–125 V and H3 ≈ ±177–188 V DC[Elektroda, ziro_9, post #18380143] Deviations > ±10 % mean the converter is not in full-bridge mode or a rail is loaded.

Does the front-panel CLIP LED show true clipping?

Yes. Tests with 4 Ω dummy load show the LED lights just before sine-wave flattening; internal yellow LEDs fire a few ms earlier for safety[Elektroda, INtRO_Tech, post #20628867]

Can I power the amp with a conventional transformer?

Yes, but weight and cost rise sharply. A 2×15 V + 2×84 V + 2×42 V 1 kVA toroid fits after removing the SMPS; delivers ≈ 1.2 kW/4 Ω total and works cool after 1 h at 50 % duty[Elektroda, INtRO_Tech, post #20627975]

What’s the safest way to first-start after repair?

Use three 100 W bulbs in parallel as a series limiter[Elektroda, zbyszekdymny, post #21049561] Verify 15 V on SG3525 pin 15, no DC on outputs, then replace bulbs with fuses.

What current can the EPBF IGBT handle?

Datasheet Ic rating is 140 A at 25 °C[IR, DS]. The non-EPBF variant is only 75 A, hence fakes halve margin and fail sooner[Elektroda, Ziemowit1973, post #20020442]

Edge case: amp reboots every few seconds – cause?

A shorted 22 pF snubber or leaking gate zener overloads one half-bridge; SG3525 detects imbalance, pulls pin 10 high, shutting PWM[Elektroda, zbyszekdymny, post #21050899]

Quick 3-step check when PSU stays silent

  1. Confirm 5 V at SG3525 pin 16 and < 0.2 V at pin 10. 2. Scope pins 11/14 for 80 kHz square. 3. If missing, swap LM339 & NE555; they latch SG shutdown[Elektroda, Robercikxxx, post #21050982]
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