A1989 Logic Board Repair Issue. One CD3215 chip is the culprit

[Stephen]

As the title states, got one CD3215 chip being a complete butthole to me. All readings on the other 3 chips read as follows
5.16V .47amp
5.16V .47amp
5.16V .47amp
5.16V .04amp (this guy is the issue) (U3200)

So I went ahead and replaced the chip, (actually 3 times with 3 new CD3215 chips) all same issue, at first it wasn't reading at all then it finally started reading. I can rest assured is it not the CD3215 chip now but something else is causing this port to not fully read (god I wish the board would just turn on so we can just recover the data)

Originally the board had 3 faulty chips (this one was one of them) replaced them, scrubbed epoxy coating and voila all chips work (except for this one). So far what I am seeing is the chip reads correctly on our EDP reader (it wasn't originally now its good)
But one area I am testing is not getting any voltage whatsoever,
Q3450 is not getting any voltage readings. Tested R3450 and not getting any voltage readings.
C3213 no voltage. So I am assuming there is definelty a short somewhere in this area. Replaced a diode and nothing has happened as well since I did notice. a chip on one of the diodes. No luck. Again I replaced the CD3215 with three brand new chips and of course they all read the same so something tells me it is not the CD3215 anymore but something else causing it. If someone can pin point me to the right areas I would be greatly appreciated!

I am also getting 1VOLT on PPBUS_G3H

[Cashcobra]

• Diagnostic solutions
  
• 0V6 diode mode on [n:USBC_TA_CC1] at [p:CB313:1]
  0V6 diode mode on [n:USBC_TA_CC2] at [p:CB314:1]
  
  5V on [p:FB200:1]
  3V3 on [p:CB308:1]
  1V8 on [p:CB305:1]
  1V8 on [p:CB306:1]
  1V1 on [p:CB304:1]
  
  ~26V on [p:QB300:1] and [p:QB300:4]
  Check [n:PPDCIN_G3H] on [p:QB300:8]
• UB400
  0V6 diode mode on [n:USBC_TB_CC1] at [p:CB413:1]
  0V6 diode mode on [n:USBC_TB_CC2] at [p:CB414:1]
  
  5V on [p:FB201:1]
  3V3 on [p:CB408:1]
  1V8 on [p:CB405:1]
  1V8 on [p:CB406:1]
  1V1 on [p:CB404:1]
  
  ~26V on [p:QB400:1] and [p:QB400:4]
  Check [n:PPDCIN_G3H] on [p:QB400:8]
• U3100
  0V6 diode mode on [n:USBC_XA_CC1] at [p:C3113:1]
  0V6 diode mode on [n:USBC_XA_CC2] at [p:C3114:1]
  
  5V on [p:F3000:1]
  3V3 on [p:C3108:1]
  1V8 on [p:C3105:1]
  1V8 on [p:C3106:1]
  1V1 on [p:C3104:1]
  
  Check 26V on [p:Q3100:1] and [p:Q3100:4]
  Check [n:PPDCIN_G3H] on [p:Q3100:8]
• U3200
  0V6 diode mode on [n:USBC_XB_CC1] at [p:C3213:1]
  0V6 diode mode on [n:USBC_XB_CC2] at [p:C3214:1]
  
  5V on [p:F3001:1]
  3V3 on [p:C3208:1]
  1V8 on [p:C3205:1]
  1V8 on [p:C3206:1]
  1V1 on [p:C3204:1]
  
  Check 26V on [p:Q3200:1] and [p:Q3200:4]
  Check [n:PPDCIN_G3H] on [p:Q3200:8]
• 5V to 20V sequence
  USBC CC1/2 & T2-SMC I2C
  Diode mode ~0V6 on [n:USB_XA_CC1] at [p:C3113:1]
  Diode mode ~0V6 on [n:USB_XA_CC2] at [p:C3114:1]
  Diode mode ~0V6 on [n:I2C_UPC_SDA] at [p:R5220:2]
  Diode mode ~0V6 on [n:I2C_UPC_SCL] at [p:R5221:2]
  
  Power getting to the CD3215...
  5V on [n:PP20V_USBC_XA_VBUS] at [p:F3000:1]
  
  Basic CD3215 voltages + LDOs...
  3V3 on [n:PP3V3_UPC_XA_LDO] at [p:C3108:1]
  1V8 on [n:PP1V8_UPC_XA_LDOA] at [p:C3106:1]
  1V8 on [n:PP1V8_UPC_XA_LDOD] at [p:C3105:1]
  1V1 on [n:PP1V1_UPC_XA_LDO_BMC] at [p:C3104:1]
  
  Open [p:Q3100] so power goes through to [n:PPDCIN_G3H]...
  >5V on [n:UPC_XA_GATE1] at [p:Q3100:1]
  >5V on [n:UPC_XA_GATE2] at [p:Q3100:4]
  5V on [n:PPDCIN_G3H] at [p:C7000:1]
  
  Power to the ISL [p:U7000] ...
  (in) 5V on [n:TBA_VDDA] at [p:C7075:1]
  (out) >=3V3 on [n:CHGR_EN_MVR] at [p:R6907:2]
  
  Getting [n:PP3V3_G3H_RTC] ...
  3V3 on [n:PP3V3_G3H_RTC] at [p:L6900:1]
  
  20V switch over...
  20V on [n:PP20V_USBC_XA_VBUS] at [p:F3000:1]
  >20V on [n:UPC_XA_GATE1] at [p:Q3100:1]
  >20V on [n:UPC_XA_GATE2] at [p:Q3100:4]
  20V on [n:PPDCIN_G3H] at [p:C7000:1]
  
  Final steps...
  5V on [n:TBA_AUX_DET] at [p:C7016:1]
  MOSFETS [p:Q7030] and [p:Q7040] should now be open
  [p:U7000] should be generating [n:PPBUS_G3H]
  
  Other things to check...
  Measure [p:R7075] for 4R7 value

if all this are check correctly you have PPBUS_G3H

[Stephen]

Update: brought thermal camera up.
U3100 Is reaching temps of 151 degrees. The meter is showing .37amps on that chip is that even normal?

[Cashcobra]

if you have short on u3100 or bad controller it will hot

can you measure and tell me what you get ?


5V on [p:F3000:1]
3V3 on [p:C3108:1]
3V3 on [p:C3100:1]
1V8 on [p:C3105:1]
1V8 on [p:C3106:1]
1V1 on [p:C3104:1]

[Stephen]

Ok so U3100 and U3200 are in the high temp ranges 5v .17amps on both ports. Other side 5v .39amps on both ports. Both chips are in the high temp range but the other side is not. I will get back to you with measurements tomorrow. I know I am getting close to solving this issue.

[Cashcobra]

Ok will be waiting

[Stephen]

F3000- 5v
c3108- 0.5v
c3100- 0.04v
c3105- 0.0v
c3106- 0.0v
c3104- 0.5v

[Stephen]

F3001:1- 5v
c3201:1-5v
c3214:1-1.7v
c3213:1-0.0v
c3209:1-0.0v
c3200:1-0.0v
c3206:1-0.0v
c3204:1-0.0v
c3219:1-0.0v
c3208:1-2.6v
c3205:1-0.4v

[Stephen]

Also keep in mind these are new chips that have been soldered on correctly. So I can rest assured the chips are not faulty at this point so there is definitely a short somewhere

[Stephen]

Bump.

[mon2]

I am also getting 1VOLT on PPBUS_G3H

Is this still true? Remove all power -> meter in resistance mode -> check the resistance to ground of PPBUS_G3H. Is it a low measurement? Remove the downstream fuses on PPBUS_G3H and check the resistance again on the removed fuse pads to confirm which side of this power rail is being shorted.

What is the exact resistance on each side of the removed fuse(s) ?

Power up again without the fuse(s) and confirm if the PPBUS_G3H voltage has returned to normal without a downstream load.