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    1. N

      Start Up Fails When HDD Connected

      Don't think so - my pic in post #81 shows that I soldered the wires directly on the cap, some distance from U24, so it shouldn't have heated appreciably. Not sure when U24 died - the HDD was running-up ok early yesterday, after I'd attached the wires and 'scoped the voltage across the cap...
    2. N

      Start Up Fails When HDD Connected

      HDD 12V switch schematic attached showing U24, now believed to be an FDC658 P-channel Mosfet (not as previously stated in post #80). Also attached, test results on a from-the-spares-drawer 4u7/50V cap for reference showing effects of freezing and recovery therefrom. Removed cap test results to...
    3. N

      Start Up Fails When HDD Connected

      Full details later but, of necessity, I've had to remove U24 (and the cap, while I was at it). On the plus side this has allowed me to reverse-engineer what turns out to be the HDD 12V switch circuit (where the problem is) and conduct out-of-circuit checks on the cap with the ESR70. The fault...
    4. N

      Start Up Fails When HDD Connected

      I attached the monitor wires to the suspect cap late yesterday morning and the PVR was returned to the lounge. As expected there were numerous boot attempts when switching on for lunch, and again late afternoon after having removed it to take the pic of the attached wires and replace the lid...
    5. N

      Start Up Fails When HDD Connected

      Thanks - yes, a possible candidate. Aussie Dave Jones's long-running EEVblog (highly recommended) covered failure of these components a few years ago - #1037: youtube.com/watch?v=QgKY5QWehME An interesting update on the problem to follow lunchtime today following some overnight tests...
    6. N

      Start Up Fails When HDD Connected

      Thanks for your comments. This is our in-service PVR (had to be returned in time for the missus to watch last night's Grand Designs over lunch) so I'm taking a "minimally-invasive" approach to minimise risk of damage to the board/domestic grief; it's easier to tack-on a couple of wires than...
    7. N

      Start Up Fails When HDD Connected

      Confidence was high that the 2N4401 was dud – but started to wane when its junctions were checked out of circuit with a DMM and nothing abnormal was found. Sure enough, after transplanting the one from the working PVR it didn’t fix the fault. Attention has returned to the nearby electrolytic...
    8. N

      Start Up Fails When HDD Connected

      I deployed the can-of-freezer strategy this morning by firstly baking the faulty PVR in the oven at 30 degrees C for 30 minutes. As found previously, it then booted ok first time (nice and warm). I used the freezer on the accessible areas of the main board (some are hidden underneath the HDD)...
    9. N

      Start Up Fails When HDD Connected

      Thought I'd confirm BH's waveforms on page 3 of this thread, so added monitor wire to U22 pin 6. Also sanitised the the HDD supplies monitoring. Then tried unplugging HDD and adding dummy loads to HDD's supplies (eg 20R across 12V = 600mA; 4R7 across 5V = 1.06A) ...and reboot problem goes away.
    10. N

      Start Up Fails When HDD Connected

      Not the cap across U52's output - adding another made no difference (but had to try). To be continued...
    11. N

      Start Up Fails When HDD Connected

      I now have a plan for tracking down the suspect electrolytic using a can of freezer - but before I go down that route, I’ll take a closer look at the timing wrt the HDD’s 5V rail of that troublesome pulse at U22’s enable pin (see BH's earlier work in this thread). I’ve attached a zoomed-in...
    12. N

      Start Up Fails When HDD Connected

      I’ve attached some further measurements on my faulty PVR. These examine the 12V and 5.8V outputs* from the power board. I’ve compared these with the 12V and 5V HDD supplies under fault-present, and fault-not-present conditions (as described in the pic titles). For ease of reference I’ve...
    13. N

      Start Up Fails When HDD Connected

      Thanks for your comments. You focussed your attention on the HDD’s +5V supply. Did you have any issues with its +12V supply, do you recall – like I have found? At one point you said that the input to the buck converter U22 which feeds U52 “is OK” (as per the ‘scope trace). Your schematic...
    14. N

      Start Up Fails When HDD Connected

      Well, those are all possible causes. However, at least conventional-style electrolytics (see the pic of the dodgy ones in the Grundig TV) are always the first port of call, especially if they are located near a heat source (such as a heatsink) which will accelerate their “drying-out”. Heat and...
    15. N

      Start Up Fails When HDD Connected

      Thanks for your comments and I have read your thread. However (as I said) I tried the power board from the fully-working spare PVR and it didn’t fix - so I don’t think that’s where the problem lies. I had hoped it was – as was the case with the Grundig TV I fixed. The attached shows that...
    16. N

      Start Up Fails When HDD Connected

      Having read through this thread, not sure what conclusions were drawn by previous contributors as it seems to have gone cold. At this time, I reckon the problem I'm having is due to a dud cap - but which one? Results attached show the problem isn't confined to the HDD's 5V supply - the 12V...
    17. N

      Start Up Fails When HDD Connected

      I’ll have a good read through this thread as I’ve been chasing-down the same (or a similar) fault with our HDR-Fox T2 for a few weeks now (since mid-Oct 2021). Fortunately, I have a fully-working spare PVR and have tried swapping the power board, the HDD and the front panel board to confirm the...
    1. N

      Start Up Fails When HDD Connected

      Don't think so - my pic in post #81 shows that I soldered the wires directly on the cap, some distance from U24, so it shouldn't have heated appreciably. Not sure when U24 died - the HDD was running-up ok early yesterday, after I'd attached the wires and 'scoped the voltage across the cap...
    2. N

      Start Up Fails When HDD Connected

      HDD 12V switch schematic attached showing U24, now believed to be an FDC658 P-channel Mosfet (not as previously stated in post #80). Also attached, test results on a from-the-spares-drawer 4u7/50V cap for reference showing effects of freezing and recovery therefrom. Removed cap test results to...
    3. N

      Start Up Fails When HDD Connected

      Full details later but, of necessity, I've had to remove U24 (and the cap, while I was at it). On the plus side this has allowed me to reverse-engineer what turns out to be the HDD 12V switch circuit (where the problem is) and conduct out-of-circuit checks on the cap with the ESR70. The fault...
    4. N

      Start Up Fails When HDD Connected

      I attached the monitor wires to the suspect cap late yesterday morning and the PVR was returned to the lounge. As expected there were numerous boot attempts when switching on for lunch, and again late afternoon after having removed it to take the pic of the attached wires and replace the lid...
    5. N

      Start Up Fails When HDD Connected

      Thanks - yes, a possible candidate. Aussie Dave Jones's long-running EEVblog (highly recommended) covered failure of these components a few years ago - #1037: youtube.com/watch?v=QgKY5QWehME An interesting update on the problem to follow lunchtime today following some overnight tests...
    6. N

      Start Up Fails When HDD Connected

      Thanks for your comments. This is our in-service PVR (had to be returned in time for the missus to watch last night's Grand Designs over lunch) so I'm taking a "minimally-invasive" approach to minimise risk of damage to the board/domestic grief; it's easier to tack-on a couple of wires than...
    7. N

      Start Up Fails When HDD Connected

      Confidence was high that the 2N4401 was dud – but started to wane when its junctions were checked out of circuit with a DMM and nothing abnormal was found. Sure enough, after transplanting the one from the working PVR it didn’t fix the fault. Attention has returned to the nearby electrolytic...
    8. N

      Start Up Fails When HDD Connected

      I deployed the can-of-freezer strategy this morning by firstly baking the faulty PVR in the oven at 30 degrees C for 30 minutes. As found previously, it then booted ok first time (nice and warm). I used the freezer on the accessible areas of the main board (some are hidden underneath the HDD)...
    9. N

      Start Up Fails When HDD Connected

      Thought I'd confirm BH's waveforms on page 3 of this thread, so added monitor wire to U22 pin 6. Also sanitised the the HDD supplies monitoring. Then tried unplugging HDD and adding dummy loads to HDD's supplies (eg 20R across 12V = 600mA; 4R7 across 5V = 1.06A) ...and reboot problem goes away.
    10. N

      Start Up Fails When HDD Connected

      Not the cap across U52's output - adding another made no difference (but had to try). To be continued...
    11. N

      Start Up Fails When HDD Connected

      I now have a plan for tracking down the suspect electrolytic using a can of freezer - but before I go down that route, I’ll take a closer look at the timing wrt the HDD’s 5V rail of that troublesome pulse at U22’s enable pin (see BH's earlier work in this thread). I’ve attached a zoomed-in...
    12. N

      Start Up Fails When HDD Connected

      I’ve attached some further measurements on my faulty PVR. These examine the 12V and 5.8V outputs* from the power board. I’ve compared these with the 12V and 5V HDD supplies under fault-present, and fault-not-present conditions (as described in the pic titles). For ease of reference I’ve...
    13. N

      Start Up Fails When HDD Connected

      Thanks for your comments. You focussed your attention on the HDD’s +5V supply. Did you have any issues with its +12V supply, do you recall – like I have found? At one point you said that the input to the buck converter U22 which feeds U52 “is OK” (as per the ‘scope trace). Your schematic...
    14. N

      Start Up Fails When HDD Connected

      Well, those are all possible causes. However, at least conventional-style electrolytics (see the pic of the dodgy ones in the Grundig TV) are always the first port of call, especially if they are located near a heat source (such as a heatsink) which will accelerate their “drying-out”. Heat and...
    15. N

      Start Up Fails When HDD Connected

      Thanks for your comments and I have read your thread. However (as I said) I tried the power board from the fully-working spare PVR and it didn’t fix - so I don’t think that’s where the problem lies. I had hoped it was – as was the case with the Grundig TV I fixed. The attached shows that...
    16. N

      Start Up Fails When HDD Connected

      Having read through this thread, not sure what conclusions were drawn by previous contributors as it seems to have gone cold. At this time, I reckon the problem I'm having is due to a dud cap - but which one? Results attached show the problem isn't confined to the HDD's 5V supply - the 12V...
    17. N

      Start Up Fails When HDD Connected

      I’ll have a good read through this thread as I’ve been chasing-down the same (or a similar) fault with our HDR-Fox T2 for a few weeks now (since mid-Oct 2021). Fortunately, I have a fully-working spare PVR and have tried swapping the power board, the HDD and the front panel board to confirm the...
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