JMBsnr 5 Posted April 2, 2020 Evening All, Due to isolation I have decided to finally getting round to finishing my Tamiya Holiday Buggy that I started many, many years ago. long story short, when I have connected the receiver, ESC and the battery, turn everything on I am getting a continuously flashing LED (plus the alarm when the motor is connected). I believe this may be due to the receiver not getting power but everything is connected, and with a brand new battery. Can anyone shed any light on what I may have done or what is going wrong? if it helps the components are and all brand new: Tamiya TEU-104BK ESC Hitec HP-2RNB AM Receiver. Share this post Link to post Share on other sites
78Triumph 2610 Posted April 2, 2020 Does the steering servo work at all? Share this post Link to post Share on other sites
Juggular 4964 Posted April 2, 2020 Above might help. Share this post Link to post Share on other sites
magpie 51 Posted April 2, 2020 hello have you got same crystals in controller and revciver. Share this post Link to post Share on other sites
JMBsnr 5 Posted April 2, 2020 8 minutes ago, Juggular said: Above might help. I saw that post earlier, it’s how I found the forum. I tried the AA battery pack that came with the transmitter and that didn’t do anything. I even tried trimming the red battery connector from the ESC to ensure it fitted correctly. Still no joy. 1 Share this post Link to post Share on other sites
JMBsnr 5 Posted April 2, 2020 8 minutes ago, magpie said: hello have you got same crystals in controller and revciver. I believe so. I purchased everything together. The receiver came with the transmitter. Share this post Link to post Share on other sites
LongRat 616 Posted April 3, 2020 The TEU104 puts full main battery voltage straight through to the receiver. Most receivers are ok with it, but I have seen it blow up a Hitec one the first time the system was connected. The receiver might have been damaged and that therefore could be the problem. However, when you tried the 4x AA pack, looks like you still had the ESC connected to the receiver supplying full battery voltage at the same time. In order to power the receiver from the AA pack, you need to disconnect the red wire from the ESC plug into the receiver to stop it feeding power in there. The white signal and black ground wires should still be present and plugged in though. 1 Share this post Link to post Share on other sites
JMBsnr 5 Posted April 3, 2020 1 hour ago, LongRat said: The TEU104 puts full main battery voltage straight through to the receiver. Most receivers are ok with it, but I have seen it blow up a Hitec one the first time the system was connected. The receiver might have been damaged and that therefore could be the problem. However, when you tried the 4x AA pack, looks like you still had the ESC connected to the receiver supplying full battery voltage at the same time. In order to power the receiver from the AA pack, you need to disconnect the red wire from the ESC plug into the receiver to stop it feeding power in there. The white signal and black ground wires should still be present and plugged in though. I had another go at connecting the x4 AA battery pack, with the main battery pack disconnected, but still no power anywhere, no beeping light. Do you think this means the receiver is blown? Share this post Link to post Share on other sites
LongRat 616 Posted April 3, 2020 No you need the main battery connected, the ESC will not get any power to it without that. You just need to ensure this power isn't passed through to the receiver - that gets its power from the 4x AA pack. Without the main battery connected, you should still be able to move the steering servo though. If you can't do this, I suspect the receiver is toast. Share this post Link to post Share on other sites
Mad Ax 9313 Posted April 3, 2020 It sounds like the Tx and Rx aren't communicating. It could be a blown receiver or a power problem from the ESC to the receiver. It could also be a faulty transmitter, damaged antenna, faulty or mismatched crystals, or many other things. Check the batteries in the transmitter. Are they new? Do all the lights come on? Check the crystals in transmitter and receiver. Pull them out, check the pins are clean, check they are of matching frequency / colour and the Tx one is in the transmitter and the Rx one is in the receiver (it's been a while but if memory serves the transmitter and receiver crystals are different. Someone please correct me if I am wrong). Unplug everything from your receiver. Fit a fresh, known-good set of AA batteries into the battery pack and plug it into the receiver. Make sure it's fitted the right way around. Fitting it backwards shouldn't damage the receiver but it will stop it powering on. Plug your steering servo into the receiver. Again, check the markings and make sure the plug is the right way around. Check that any endpoint adjustment on your transmitter is set to the middle value and the trims are also centralised. Your transmitter might not have endpoint adjustment. In theory, if your radio is working properly, the servo will move when commanded by one of the sticks on the radio. Try both receiver ports (throttle and steering, or Ch1/Ch2 depending how it is labelled) and both sticks or wheel/trigger on the radio to ensure all channels are working properly. If it works, your radio is fine. Let us know how you get on with that, if the radio is OK we can try to work out why the ESC isn't working. 1 Share this post Link to post Share on other sites
JMBsnr 5 Posted April 3, 2020 1 hour ago, LongRat said: No you need the main battery connected, the ESC will not get any power to it without that. You just need to ensure this power isn't passed through to the receiver - that gets its power from the 4x AA pack. Without the main battery connected, you should still be able to move the steering servo though. If you can't do this, I suspect the receiver is toast. I think you may be right. Even with connecting it as you suggest, nothing was happening. Share this post Link to post Share on other sites
JMBsnr 5 Posted April 3, 2020 53 minutes ago, Mad Ax said: It sounds like the Tx and Rx aren't communicating. It could be a blown receiver or a power problem from the ESC to the receiver. It could also be a faulty transmitter, damaged antenna, faulty or mismatched crystals, or many other things. Check the batteries in the transmitter. Are they new? Do all the lights come on? Check the crystals in transmitter and receiver. Pull them out, check the pins are clean, check they are of matching frequency / colour and the Tx one is in the transmitter and the Rx one is in the receiver (it's been a while but if memory serves the transmitter and receiver crystals are different. Someone please correct me if I am wrong). Unplug everything from your receiver. Fit a fresh, known-good set of AA batteries into the battery pack and plug it into the receiver. Make sure it's fitted the right way around. Fitting it backwards shouldn't damage the receiver but it will stop it powering on. Plug your steering servo into the receiver. Again, check the markings and make sure the plug is the right way around. Check that any endpoint adjustment on your transmitter is set to the middle value and the trims are also centralised. Your transmitter might not have endpoint adjustment. In theory, if your radio is working properly, the servo will move when commanded by one of the sticks on the radio. Try both receiver ports (throttle and steering, or Ch1/Ch2 depending how it is labelled) and both sticks or wheel/trigger on the radio to ensure all channels are working properly. If it works, your radio is fine. Let us know how you get on with that, if the radio is OK we can try to work out why the ESC isn't working. The only thing I haven’t tried is looking at the crystals. I have assumed that as it is all part of the same kit it would be correct. How would I check the crystals? Share this post Link to post Share on other sites
Mad Ax 9313 Posted April 3, 2020 There should be a label on them detailing frequency number and/or colour. The one in the transmitter should be the same as the one in the receiver. I don't recall if there is a difference between transmitter and receiver crystals but if there is it should be marked on the label (probably Tx for transmitter and Rx for transmitter). It's also worth pulling them out of their sockets and making sure the pins aren't corroded or damaged. Also check the antennas on both Tx and Rx to make sure they're not cut or broken. The Rx antenna wire should be fully unwound and standing upright and the Tx antenna fully screwed in and extended. I have known them work while not extended / wound up but range is limited; extend everything fully to give it the best chance of working while diagnosing. 1 Share this post Link to post Share on other sites
JMBsnr 5 Posted April 3, 2020 Thanks for everyone’s help, I think I have at least diagnosed where the problem sits. I have another Tamiya RC car that I had built before, many years ago that I know works fine. I therefore tried the transmitter & receiver from the old car and plugged the ESC, servos etc from the Holiday Buggy into the old cars receiver, and hey presto everything worked. So I at least know it is the receiver (or the transmitter, but that all turns on ok) that is not working. Unfortunately the 27mhz crystals are different shapes so I can’t try swapping them over. Looks like it would be a new receiver, unless there are any other final ideas on how I could test the crystals or can you even buy replacement crystals? 1 Share this post Link to post Share on other sites
LongRat 616 Posted April 3, 2020 Definitely worth checking the crystals like Mad Ax suggested, the Tx and Rx crystals are NOT the same and the Tx one must not be plugged into the receiver or it won't work. I think the most likely problem is that the receiver has blown up due to seeing unregulated pack voltage through the 104 ESC. 1 Share this post Link to post Share on other sites
JMBsnr 5 Posted April 3, 2020 15 minutes ago, LongRat said: Definitely worth checking the crystals like Mad Ax suggested, the Tx and Rx crystals are NOT the same and the Tx one must not be plugged into the receiver or it won't work. I think the most likely problem is that the receiver has blown up due to seeing unregulated pack voltage through the 104 ESC. Your probably right. I have actually managed to swap over the crystals into my other car & transmitter and they work fine. So I now know what needs to be replaced, the receiver unit. Do you need to match the brand of the receiver unit to the brand of the transmitter or are they interchangeable? Share this post Link to post Share on other sites
Mad Ax 9313 Posted April 3, 2020 Some brands will work with other brand receivers but ideally you would replace with a receiver for the same brand and radio type. There are a few used Hitec receivers on ebay right now. If you wanted to spend a little bit more you could upgrade to 2.4GHz and do away with antennas, crystals, glitches and all the rest that goes with older radio sets. 1 Share this post Link to post Share on other sites
Juggular 4964 Posted April 3, 2020 Inexpensive option) You can try ebay for similar AM crystals. You can get either 1 receiver crystal, or 1 pair. They have to match, obviously. Also, you can't put 27mhz pair to where 75mhz pair used to be. It would be better to go as close as before, even within the 27 or 75mhz band. For example, if the radio and transmitter had a pair of 75.890mhz? Then a pair of 75.970 would work fine. But I've had a situation where 75.970 pair didn't work with a radio set that used to have a pair of 75.120mhz crystals (don't remember the exact mhz, but it was far a part within 75mhz). It was as if the radio and receiver were somehow tuned for upper and lower 75mhz pairs. I don't know if radio sets are segregated in different groups, or it was a weird fluke. I'd be mindful to choose a set of xtals close to the ones you had before. If crystals don't work, then you'd need to replace the receiver or transmitter. But you have to find out which doesn't work. As you tried to do, swapping crystals would be useful in diagnostics. FYI, Crystals are uniform in size. It's just that some are wearing caps. (some are even glued. If it doesn't come out easily, don't force it. If you damage it, you could have 2 sets of radios that don't work) Expensive option) As Mad Ax mentioned, $45 for Flysky GT3C radio set + $20 for Hobbywing 1060 ESC will solve the problem. And you get to play with a 2.4hz digital radio. And you can add one extra receiver for $9 each. Flysky GT3C can control up to 10 cars (not at the same time). This is why my Tamiya cars have been increasing like bunnies (to my wife's dismay, she married a Tamiya breeder!). 1 Share this post Link to post Share on other sites
JMBsnr 5 Posted April 6, 2020 Update for everyone. Through everyone’s help I diagnosed that it was a blown receiver unit. Got a replacement off eBay, which arrived today. Finished off the body and soon had running round the garden. 3 Share this post Link to post Share on other sites