TEK MEDIA GROUP BROADCAST ENGINEERING · DIAGNOSTICS UNIT
⚠️ TECHNICAL BULLETIN 2026-14 · MPEG-4K

SRW-5100 · MPEG‑4K compression & transport

SR‑Lite/MPEG‑4K codec anomalies, cold solder on codec board, head amp gate drift & reference input decay

⧉ SRW-5100 SPECIFIC — The 5100 is Sony's MPEG-4K recorder (SR‑Lite) based on SRW-5000 mechanics but with unique codec board BKMW‑500 and 4K video processor. Systemic failures include codec sync loss, reference genlock drift, and compression engine freeze. Below: diagnostics for the MPEG realm.
E-9101 · E-9105

Codec PLL / FPGA configuration glitch

Root Cause

The BKMW‑500 MPEG‑4K codec board uses high‑speed PLLs for 4:2:2 10‑bit compression. Aging crystals (24.576 MHz, 74.25 MHz) drift or develop micro‑cracks. Deck fails to lock to 4K input or outputs tiled blocks (“confetti”).

Symptom

E-9101 (MPEG SYNC LOST) or E-9105 (STREAM ERR) during 4K recording/playback. HD modes work fine.

Fix

Replace X601, X602 on BKMW‑500. Reflow FPGA BGA if thermal cycling changes behaviour. Verify 1.2V core supply ripple < 30mV.

channel condition LED flicker

Preamp bias / gate voltage shift

Root Cause

SRW-5100 head amp (HY‑99A) uses aged differential pairs. Gate bias for MR heads drifts, causing one channel to have lower RF envelope. Deck misinterprets as dirty heads or bad tape, but cleaning does nothing.

Symptom

Playback has sparkles in one quadrant of 4K image; RF test points show one head pair envelope 6dB lower than others. Condition LEDs blink amber.

Fix

Measure gate voltage at TP‑HF (HY‑99A) per service manual. Adjust RV1/RV2 to re‑centre bias. If unstable, replace aged transistors (2SC3356).

E-9202 · E-9204

Reference input termination corrosion

Root Cause

BNC REF input on rear panel develops oxidation on internal 75Ω termination relay contacts. Deck intermittently loses genlock, especially in facilities with bi‑level/tri‑level mixed references.

Symptom

E-9202 (REF LOST) or E-9204 (GENLOCK FAIL). Works after reseating BNC, then fails again after thermal change.

Fix

Bypass the termination relay by hardwiring a 75Ω terminator on a feed‑through; replace relay RLY401 (DX‑2F‑5V) on SS‑98 board.

downconvert mode stuck

Scaler I²C lockup

Root Cause

The scaling FPGA on PR-105 board communicates via I²C bus. Marginal pull‑up resistors cause bus hang when switching between 4K and HD modes. Deck outputs only 4K or only black.

Symptom

Can't get HD‑SDI out when playing 4K tape; menu shows “downconvert” but no signal. Power cycle restores temporarily.

Fix

Replace pull‑up resistor arrays (RN104, RN105) on PR‑105 with 4.7kΩ. Reflash scaler firmware from maintenance menu (v2.3 or later).

E-0501 · E-0502

Fan tach sensor / controller failure

Root Cause

The 5100 uses a PWM fan controller with tach feedback. Electrolytic capacitors on controller board (PS‑107) dry out, causing false fan fail detection. Deck shuts down to protect codec even if fans spin.

Symptom

After 20‑30 min, deck displays E-0501 (FAN1) or E-0502 (FAN2) and powers down. Fans audibly running.

Fix

Replace 100µF/25V caps on PS‑107 near IC1. Clean fan connectors and reflow tach signal path.

uncommanded play/stop

Key matrix ghosting

Root Cause

Front panel membrane contacts develop high resistance, causing matrix decoder (HD64F3048) to misinterpret key presses. Deck may start playback spontaneously or ignore stop command.

Symptom

In local mode, deck behaves erratically: PLAY engages without touch, or buttons need hard press. Remote control unaffected.

Fix

Disassemble front panel, clean carbon contacts with isopropyl. Reapply conductive grease. If CPU port damaged, replace panel PCB (A‑8273‑180).

macroblocking / audio pops

Buffer SDRAM timing drift

Root Cause

Codec board uses 256Mb SDRAM for stream buffering. Aging solder balls or timing drift cause random bit errors, visible as macroblocks in 4K image or audio CRC errors in embedded PCM.

Symptom

Playback of known good tape shows intermittent tiling artefacts, audio dropouts. Replaying same section yields errors at different positions.

Fix

Run SDRAM burn‑in test in maintenance mode (service menu 4‑2‑3). Replace ICs on BKMW‑500 if >10 errors. Reflow BGA with hot air if marginal.

intermittent freeze · no error code

PS‑106 regulator ageing

Root Cause

The 1.2V core supply for the MPEG encoder/decoder is generated on PS‑106. Output capacitors (OS‑CON) lose capacitance, causing ripple >50mV. FPGA logic randomly corrupts.

Symptom

Deck works for hours, then suddenly freezes with last frame held. No error logged. Power cycle fixes temporarily.

Fix

Replace all 560µF/4V polymer caps on PS‑106 with low‑ESR types. Monitor 1.2V ripple with scope; must be <25mV.

⚡ DIAGNOSTIC PROTOCOL — TEK MEDIA GROUP LABS (SRW-5100)

For Stubborn MPEG-4K Cases

  • 4K vs HD isolation — if error appears only in 4K mode, suspect BKMW‑500 codec board or its PLLs. HD mode uses different signal path.
  • Thermal cycle on codec board — apply gentle heat (40‑50°C) to BKMW‑500. If E‑9101 appears, reflow crystals and FPGA.
  • Monitor 1.2V rail with long persistence — micro‑dropouts on core supply cause codec crashes without triggering low‑voltage alarm.
  • Check MPEG elementary stream via TS‑OUT — connect to analyser; continuous CRC errors indicate buffer memory issue, not tape path.
  • Reference input termination test — measure DC voltage at REF input (should be 0V). If any DC present, replace input coupling cap.
  • Fan tachometer emulation — for troubleshooting E‑050x, you can temporarily pull tach lines high with 10kΩ to 5V; if error disappears, fan controller is bad.
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