Zinwell ZMT-640PVR - any advantage in running an SSD drive?

My unit (thankfully) still seems to run pretty well, and is now secondary to a newer Panasonic.

I find it quite often gives segments where the whole screen goes pixelated/fragmented for maybe 2 seconds, and more rarely towards the middle of a program, the remainder is badly pixelated, to the point where it is unviewable.

I've often wondered whether there would be an improvement in the performance, by replacing the (now) 5yr old drive with an SSD (also 250Gb).

Wonder whether anyone has tested this at all?

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Permalink Reply by Biggles on August 6, 2014 at 12:40

The HDD has nothing to do with pixellation and freezing which is a signal strength problem. SSD would allow faster access to recorded files but very expensive compared to standard drives.

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ZinwellPermalink Reply by Graham Wilson on August 6, 2014 at 14:40

I haven't tried an SSD but the drive that is fitted in the 640 is not a standard PC hard drive. Zinwell used a drive that is designed for continuous video streaming. This same drive was also used in the ZHD-USBP35 which was the add on hard drive intended to be used with the ZMT-620 & 630 models.

During the time that I was servicing the ZMT-640PVR model, I never had a hard drive failure (only one with a broken connector).

The pixellation and freezing issue is more likely to be related to the amount of data that the 640 now has to process. The CPU is trying to process data from the two incoming transport streams and with all the extra channels that have been added during the past couple of years, the amount of data now far exceeds the original design specs and capability of the 640.

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Permalink Reply by Biggles on August 6, 2014 at 15:32

If the CPU and video processing can't handle the load it would indicate the unit is not fit for the purpose under the CGA. The amount of data handling should have been foreseen and allowed for. I've had 3 STBs since 2008 (2 Zinwells and a Hyundai). All died around 2 yrs old. The power supplies just aren't up to the task. On the other hand I've had 2 Panasonic Blu Ray recorders since 2011 and never a problem. You get what you pay for.

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Permalink Reply by Bruce Glover on August 6, 2014 at 16:40

Thanks guys for the replies...

*** Biggles - price of the drive isn't a concern as I have a few laying around after testing in laptops, pc's, etc. We never watch stuff live through the Zinwell, so it's all recorded material that I'm talking about. Mainly visible when fast forwarding.

*** Graham - thanks for that... I'm thinking that because an SSD won't have any problem with keeping pace, it should show up whether the issue is a cpu/crunching issue or a drive issue.

So it's simply a case of swapping the drive out for the SSD, then going into the menu via the remote and formatting the drive?

As I now have a new Panasonic unit, it's more my interest than anything else, but I guess if it got it going well again, I'd probably start using it as well.

On the 'stuff it now has to crunch' issue... I wonder if manually trimming the channels back to only the 4 that we actually watch, might help?

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ZinwellPermalink Reply by Graham Wilson on August 6, 2014 at 17:42

Trimming channels wont help. I haven't tried an SSD, but I suspect this wont help either. (Incidently drives larger than 250GB can be used but they will only format to a maximum of 250GB) It is the current amount of EIT data which causes the problems and this is duplicated on each mux (the CPU is having to process two muxes with EIT data for every Freeview channel added to each mux). Manufacture of the ZMT-640PVR was discontinued in late 2008 with the last software update (v1.24) released in about Nov/Dec 2011 which took into account the channel restacking that Freeview carried out about that time. Since then TV3 & Prime have added regionalisation (3 copies of TV3 and 3 copies of Prime) and a number of additional channels have also been added with EIT (technical name for the Electronic Program Guide) data for each new channel and each additional regional channel. Also a new mux has recently been added with further channels to come. The amount of EIT data being received is now nearly twice what the 640 was designed to handle and this is what is causing the sluggish operation, poor response to the remote and recording failure.

As an (unsatisfactory) work around during playback of recordings, you can temporarily disconnect the aerial which removes the 2 incoming transport streams and all the EIT data and allows the microprocessor to handle just the playback functions alone without interruption from other tasks. Disconnecting the aerial will return the play, FF, Rew functions back to normal, but won’t fix miss-recorded programs. If you decided to try this, I suggest connecting a VCR female to male extension lead between your existing aerial lead and the RF input socket on the back of 640 and then disconnecting at the junction of the 2 leads rather than continually disconnecting and reconnecting from the back of the 640 as the RF input sockets are not designed for repeated disconnection and reconnection.

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Permalink Reply by willis on August 6, 2014 at 18:50

3 copies of prime and tv 3 doesnt apply to freeview hd where only 1 of each tv 1,3,prime goes into each region

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ZinwellPermalink Reply by Graham Wilson on August 6, 2014 at 21:15

Are you sure that the EIT (EPG) data is not duplicated as the analysis that I received back from the design lab in Taiwan, when they first investigated this issue, indicated otherwise.