KOATCBS 7.4 Playback Error on 4th-Gen Tablo — Silver City, NM — Exhausted Troubleshooting

[Derwood]

I’m hoping someone here might have an idea before I give up on my 4th-generation Tablo and replace it with another OTA DVR/tuner.

The problem involves KOATCBS 7.4 in Silver City, New Mexico (ZIP 88061). This is the new CBS service recently added to KOAT.

The problem

The Tablo channel scan finds KOATCBS 7.4, identifies it correctly, and shows full/excellent signal strength. The scan identifies it as 720p.

However, selecting 7.4 results in a playback error stating the following “Failed to load. A network error occurred. An unrecognized error occurred.” and the channel will not play.

This ONLY happens with 7.4. All of the other OTA channels work normally.

Importantly, KOAT 7.1 works perfectly and shows full signal strength. My understanding is that 7.1 and 7.4 are both carried on the same physical RF channel/multiplex from the same KOAT Silver City transmitter.

Interesting history

When this CBS channel was first added, 7.4 actually DID play through the Tablo.

The initial problem was that the Tablo guide information for the new channel wasn’t populated.

After going through rescans/guide updates/etc. trying to correct the guide, the guide information eventually became correct — but then 7.4 stopped playing and began producing the playback error.

I have not been able to get it to play since.

Troubleshooting performed

I have tried all of the following:

• Rebooted the Tablo multiple times.
• Completely power-cycled the Tablo.
• Rebooted the streaming devices.
• Confirmed the Tablo is running the current firmware.
• Removed/deselected 7.4 from the channel lineup.
• Saved the lineup with 7.4 removed.
• Updated the guide.
• Performed a fresh channel scan.
• Re-added 7.4.
• Saved the new lineup.
• Updated the guide again.
• Repeated the remove/save/rescan/re-add process multiple times.
• Tested with the Tablo’s built-in antenna amplifier enabled.
• Tested with the Tablo’s built-in antenna amplifier disabled.
• Tested playback through two Onn Google TV/Android TV streaming devices.
• Tested playback through the Tablo iPhone app.
• Tried recording programming from 7.4. Recording fails as well.
• Enabled Audio Compatibility Mode after the iPhone app specifically suggested doing so.
• With Audio Compatibility Mode enabled, I initially got a different behavior where 7.4 did not immediately produce the playback error but simply sat there trying to load indefinitely.
• After that initial attempt, it returned to producing the normal playback error.
• With Audio Compatibility Mode still enabled, I again removed 7.4, saved the lineup, updated the guide, rescanned, re-added 7.4 and updated the guide. It still does not work.
• Performed a complete factory reset of the 4th-generation Tablo and set it up again from scratch. The problem remains.
• I have also tried changing zip codes in the channel setup but this also did not result in a change in behavior.

Direct TV tuner test

This is probably the most important troubleshooting result.

I disconnected the Tablo from the equation and connected an OTA antenna directly to a television.

After scanning for channels on the TV:

KOATCBS 7.4 played normally.

All of the other channels worked as well.

The antenna I used for this test was actually the small indoor antenna that came with the Tablo, in a less-than-ideal temporary location.

I then took that same Tablo-supplied antenna that successfully received 7.4 on the television and connected it directly to the Tablo.

After rescanning:

7.4 still produced the playback error on the Tablo.

So the same antenna can receive and play KOATCBS 7.4 when connected directly to a television, but the Tablo cannot play 7.4 from it.

Outdoor antenna / signal testing

The Tablo is normally connected to an Onn outdoor OTA antenna.

I initially wondered whether its amplifier, excessive signal strength, multipath, or antenna direction could be responsible.

However:

• Tablo’s internal amplifier has been tested both ON and OFF.
• The separate Tablo indoor antenna was also tested as described above, with the same failure.
• The outdoor antenna is already pointed directly toward the transmitter site.
• KOAT 7.1 (An ABC affiliate) shows full signal strength and plays flawlessly.
• KOATCBS 7.4 also shows excellent/full signal strength during the Tablo channel scan.

Therefore this doesn’t appear to be a simple weak-signal or antenna-aiming issue.

What makes this particularly strange

The combination of symptoms is:

KOAT 7.1: Full signal, works perfectly
KOATCBS 7.4: Full signal, detected correctly, will not play or record
7.4 connected directly to TV: Works normally
Same antenna connected to Tablo: 7.4 fails
Other Tablo OTA channels: Work normally
Factory-reset Tablo: 7.4 still fails
Multiple Tablo client devices: Same failure

And again, 7.4 initially worked on this Tablo before the guide/channel-lineup troubleshooting was performed.

Tablo support

I have also been working with Tablo support.

Unfortunately, both phone and email support have mostly continued suggesting basic troubleshooting steps that I had already performed and described to them. I have asked for the issue to be escalated and for someone to examine the Tablo’s diagnostic logs, but so far I haven’t received any useful technical explanation.

What I’m wondering

Has anyone encountered a situation where one specific subchannel within an otherwise-working OTA multiplex is detected at full strength but cannot be played or recorded by a 4th-gen Tablo, while a normal television tuner plays that same subchannel without a problem?

I’m particularly wondering about:

• MPEG-2/MPEG-4 or other codec compatibility
• AC3/audio stream issues
• PMT/PID/PSIP or transport-stream differences
• Some unusual encoding parameter on the new 7.4 CBS feed
• A Tablo firmware bug involving this particular stream
• Stale/incorrect guide or station metadata, especially since 7.4 originally played before the guide information was corrected
• Anything else specific to newly added OTA subchannels

At this point I believe I have exhausted the normal antenna, signal, rescan, guide, app, reboot and factory-reset troubleshooting.

I’m considering replacing the Tablo with an HDHomeRun FLEX DUO, but I’d really prefer to get the Tablo working if someone here recognizes these symptoms or knows of another diagnostic/fix I can try.

Any ideas — particularly from anyone familiar with the technical side of the 4th-generation Tablo tuner/playback system — would be greatly appreciated.

[justalurker]

@Derwood

This whole KRQE/KOAT/CBS thing has been a nightmare and handled poorly by Tablo and TiVo and the stations. KOAT has been unresponsive to complaints.

You might try changing your ZIP code/location in the Tablo settings to see if there is any improvement.

I asked AI and here’s what it said…

[Ron1]

Rabbitears shows a ton of translators for KOAT. Is it possible Tablo is picking up more than one and using one for 7.1 and a different one for 7.4?

RabbitEars.Info

[zippy]

Another possibility is that most DVRs like tablo require that the PSIP data is all there and correct. TV’s don’t care very much. But I don’t if a gen 4 detects a channel under that situation but later can’t process the channel for play back. But tablo support could easily connect in to your device and tell what is happening.

And most TVs can tell you what audio format is in the stream plus SAP information.

[CarbonCompound]

KOAT 7.4 from Albuquerque wouldn’t be visible to your antenna. It’s northeast of your location.

K08QP is the translator used just north of Silver City.

Tablo Gen4 has poor tuner sensitivity and it also does some realtime decoding which I don’t understand but told it’s special. It also splits the signal by the number of tuners.

If you’re using the mudflap antenna it needs to be in line-of-site to the translator.

[justalurker]

@Derwood

I scored one of these last week and it blows my Mohu Leaf away. More channels and signal.

Hung in same window 25 miles from broadcast towers line of sight.

Might be worth a try down there in Silver City.

https://www.youtube.com/watch?v=-YfDK3kQRHk

[CarbonCompound]

Other things to consider:

1. The transmitter is 1548’ AGL
2. Power is only .3kW
3. Signal is VHF-HI RF8

Those mudflap antennae aren’t VHF friendly. If you get a signal it’s from the wires not the antenna.

VHF signals penetrate but ATSC 1 is prone to multipath interference. Reflected signal in mountainous region.

Depending upon your distance from the transmitter you may want to increase the antenna elevation to focus more on the signal rather than ground clutter.

Your precise location will determine if you are in a green zone or yellow or blind spot.

[Derwood]

@justalurker

This whole KRQE/KOAT/CBS thing has been a nightmare and handled poorly by Tablo and TiVo and the stations. KOAT has been unresponsive to complaints.

You might try changing your ZIP code/location in the Tablo settings to see if there is any improvement.

I asked AI and here’s what it said…

I agree this has been handled very poorly by all involved. Fortunately I have only been affected by one channel–so far. I hope it gets better in the future. I have tried changing the zip code in the programming guide as well as several rescans of the channels but no luck yet.

@Ron1

Rabbitears shows a ton of translators for KOAT. Is it possible Tablo is picking up more than one and using one for 7.1 and a different one for 7.4?

I suppose it’s possible but I receive all other sub-channels from K08QP, since 7.4 has only been operational for a month I highly suspect it has more to do with configuration than a signal problem.

@zippy

Another possibility is that most DVRs like tablo require that the PSIP data is all there and correct. TV’s don’t care very much. But I don’t if a gen 4 detects a channel under that situation but later can’t process the channel for play back. But tablo support could easily connect in to your device and tell what is happening.

And most TVs can tell you what audio format is in the stream plus SAP information.

I will keep bugging support and hope they eventually get away from telling me to repeat the troubleshooting tips I’ve done numerous times and actually start digging into the problem . Good idea about the TV displaying the audio format, I will check and compare across the channels, perhaps 7.4 is different than the rest..

@CarbonCompound

KOAT 7.4 from Albuquerque wouldn’t be visible to your antenna. It’s northeast of your location.

K08QP is the translator used just north of Silver City.

Tablo Gen4 has poor tuner sensitivity and it also does some realtime decoding which I don’t understand but told it’s special. It also splits the signal by the number of tuners.

If you’re using the mudflap antenna it needs to be in line-of-site to the translator.

You are correct, my local transmitter is KO8QP-D, although in all guides and menus Tablo refers to that channel as 7.4 KOATCBS. My primary antenna for the last 2 years has been a multi-directional outdoor antenna mounted 12’ AGL with a direct line of sight to the transmitter which is less than 6 miles away. All channels come in at full strength and all sub-channels except 7.4 work without issue.

@justalurker

I scored one of these last week and it blows my Mohu Leaf away. More channels and signal.

Hung in same window 25 miles from broadcast towers line of sight.

Might be worth a try down there in Silver City.

Thanks for the suggestion but I really don’t think signal quality is the problem.

@CarbonCompound

Other things to consider:

1. The transmitter is 1548’ AGL
2. Power is only .3kW
3. Signal is VHF-HI RF8

Those mudflap antennae aren’t VHF friendly. If you get a signal it’s from the wires not the antenna.

VHF signals penetrate but ATSC 1 is prone to multipath interference. Reflected signal in mountainous region.

Depending upon your distance from the transmitter you may want to increase the antenna elevation to focus more on the signal rather than ground clutter.

Your precise location will determine if you are in a green zone or yellow or blind spot.

I am in a green zone with direct line of sight to the transmitter…Multiple types of antennas have been used at various locations around my house pointed in several directions have all resulted in the same outcome…I receive all channels except 7.4. Thanks for the ideas though.

[justalurker]

@Derwood

@ 6 miles line of sight you may have too much antenna.

I found the antennas that Tablos come with underwhelming. I’m 25 miles from the towers with line of sight and the Tablo antenna wouldn’t pull in channels my Leaf did.

The Philips antenna I referenced adding a bunch more channels and higher signal strength can either of the others in the same window.

Have you reported the recpetion problem to KOAT @ outages@koat.com

I don’t believe the problem will be solved by Tablo support rather it is a site problem and you will have to try everything until you are completely defeated or get 7.4.

[Ron1]

@Derwood

However, selecting 7.4 results in a playback error stating the following “Failed to load. A network error occurred. An unrecognized error occurred.” and the channel will not play.

That doesn’t sound like a signal problem. It sounds like your Tablo tried to fetch some data from a Tablo server and didn’t get it. Most likely the problem is at the server end.

Poster @Roger_Smith had the same problem on a different station a month ago. Don’t know if he ever got it fixed.

Failed to Load. A network error has ocurred

Quad tuner. Zip code 86409. Channel 3.3 (Grit) gives me an error (attached), this is from the IOS beta app. Does the same on the tvOS beta app. Did this prior to the beta also. I haven’t brought it up before because it works perfectly on my Legacy Quad Tuner. Same antenna for both. Ideas? Need more info? [IMG_0300]

[Ron1]

Is there any way you can force Tablo’s offline mode? Maybe by disconnecting your modem/router’s internet connection. Offline mode is supposed to let you watch live TV without using the internet. If you can watch 7.4 in offline mode then you will know the problem is with Tablo’s server.
https://support.tablotv.com/hc/en-us/articles/38166453010196-Using-Offline-Mode-on-4th-Generation-Tablo-Devices

[Derwood]

@Ron1

That doesn’t sound like a signal problem. It sounds like your Tablo tried to fetch some data from a Tablo server and didn’t get it. Most likely the problem is at the server end.

Poster @Roger_Smith had the same problem on a different station a month ago. Don’t know if he ever got it fixed.

That is the same exact error I get on this channel…

@Ron1

Is there any way you can force Tablo’s offline mode? Maybe by disconnecting your modem/router’s internet connection. Offline mode is supposed to let you watch live TV without using the internet. If you can watch 7.4 in offline mode then you will know the problem is with Tablo’s server.
https://support.tablotv.com/hc/en-us/articles/38166453010196-Using-Offline-Mode-on-4th-Generation-Tablo-Devices

Brilliant idea! In offline mode the channel works perfectly. No playback errors at all. I would say this gives me definitive proof the issue is on Tablo’s side and not anything to do with the signal. Hopefully Tablo support will do something to fix it.

[justalurker]

@Derwood

I’ve had the “failed to load” error a couple times and closed the IOS app then restarted and it went away.

Curious though… is the Tablo connected to your network by WiFi or Ethernet?

[Ron1]

Thanks for letting us know the offline mode trick worked. Fingers crossed Tablo fixes it.