There are many uses for a good current source, in particular, to drive a noise generator, Noise Source TWS-N15. Not much to write home about, but because of frequent requests, I am publishing the circuit here. It will work for small current from 2 or 3 mA up to 10 or 20 mA with no problem, and very little drift over temperature and time. For R, uses a good resistor. Input voltage can be up to 35 V, or even higher.
This blog is hosted by a professional provider, but the manuals archive (which needs quite a bit of storage), and other webpages, and my fileserver, is running on two machines, a Dell OptiPlex FX160 as the main, eco-efficient system (in Germany), and a Dell PowerEdge SC1425 with a Raid 1, 3 TB hard drive system as the backup, and currently my main system in Japan (where I am living on a temporary business assignment). Recently, the SC1425 failed, it just would not start up anymore. Power supply seems OK – likely, a severe issue. Checked all the memory and everything, but to no avail.
After fiddling around for about 2 hours, and still no success, I decided to order a new server – a new old server, Dell PowerEdge 850. Just about 35 Dollars used. Rather than 2x XEON processors, it has a Pentium D, 3.2 GHz Dual-Core. Plenty of power for a web- and fileserver.
A couple of days later, the unit arrived – removed the SATA Raid controller (running on Ubuntu with software Raid), and some BIOS settings (activate SATA, disable Keyboard error, enable boot from USB, default power up status is ON) plus BIOS Update. Also, reconfigured the router to make sure this machine will get all the HTTP requests.
A few tests – the harddrive is working fine, about 100 MB/s (sure there is a cache). The Raid 1 is up with no repairs or anything.
A quick check – also the web server is reachable.
I wouldn’t recommend a single PowerEdge for your super critical applications, but they are pretty good for the current cost, as long as you don’t mind the fan noise.
For year I have been using various Molex style connectors, 2.5 mm, 3.96 mm, and so on, but never by crimping own contacts. Criming is a special art, and if not done properly, it can cause all kinds of reliability issues. So I usually purchased pre-crimped wires, and just assembled them for contact blocks. In other cases, I just used regular pliers to mount wires to contacts, and soldered them in (best, to pre-tin the wire, then mount it in the contact with small pliers, then solder it in – this will result in a very reliable connection. Also, never use low quality wire, only full copper core, heavily tinned wire, UL 1007 or similar.
But why not try to crimp contacts ourselves and add a new capability to the workshop? So I went ahead, and ordered a low cost pair of crimping pliers, EUR 12, not bad.
It made it from China to Japan very quickly, delivered by a friendly postman (here they are very friendly). That’s the tool: quality looks quite OK, and the steel is pretty hard. Sure this is not a high throughput production tool – I am looking at a few 10s of contacts every year, not 1000s.
Step 1, remove the insulation from the wire, and get the contact and pliers ready.
Step 2, insert the contact in the pliers, and close it until flush (don’t apply much force).
Step 3, insert the wire, and crimp the inner connection. Don’t get any of the insulation caught up by the crimp. It is a bit inconvenient to get the contact out of the pliers, probably will make a special tool for it (a U-shape bent piece of steel sheet metal to push out the contact).
Step 4, Inspect the inner crimp. Use a magnifier if necessary (make sure no plastic and insulation got into the crimp area). Pull on the wire, it must be firmly held (a properly crimped wire can’t be pulled out by any reasonable force).
Step 5, slightly close the insulation crimp using the tip of the pliers.
Step 6, establish the insulation crimp.
Step 7 – It’s ready. Inspect. Carry out pulling test.
Looking for the CRT front bezel and frame to fix another unit, I found this 8412A Phase Magnitude Display on a Japanese auction site for EUR 8 plus shipping, really affordable! Also, I believe it to be a great source of spare parts, because there are many of the HP standard semiconductors of the 70s inside.
The unit arrived in great shape, almost too good to take it apart – maybe we can use it for something cool, like a CRT clock or some soundwave visualization unit?
How to get it to work – checked the 8412A manual, and, unfortunately, it needs a whole lot of unusual supply voltages (the 8412A slides into the 8410A/B Network Analyzer mainframe) – not easy to operate it without the mainframe. 175 Volts AC, to drive the CRT and 6.3 VAC heater, and +-20 VDC, for the other circuits.
Some pictures of the unit…
The dangers of high voltage are fairly obvious!!
Quite similar to other HP units – amazing how often they recycled the design!
2.000 kOhm, +- 0.05% resistors, a matched pair – not bad! Definitely, a lot of good parts in this unit, including high voltage parts, a good CRT, many semiconductors and transistor pairs, mica capacitors, etc.
HP even supplied a small test board to make service and adjustment easier! Great!!
This is one of the worst electronic gadgets that my workshop has every seen, a US TEO Brand A5951 USB charger. Usually, not much can go wrong with the design of a 5 V switchmode power supply, but with this device, all went wrong, a combination of bad design, bad manufacturing, and non-existing sense for product responsibility.
Can you see the wires – right hand side is low voltage side, left hand side is mains! Can you see the solder stuck to the board – almost connecting mains and low voltage?
The only “safety” function I can see if a PCB trace fuse (left hand side zig-zag) on a mildly flammable paper board.
Even the case isn’t sealed – the manufacturer is even saving the glue!
That’s the brand name and numbers, if you have one of these, take it out of service immediately!
Seems Canada has some clever authorities – they found a whole lot of unsafe USB chargers. Remember the good old days when it was illegal to import just any kind of crap?
Recently, I have moved a U2508 milling/drilling machine to my Ludwigshafen workshop (from the remote workshop, where there is more space for heavy machinery). It’s a really good machine, slim, but very well built and useful for all kinds of drilling and milling work. It has an automatic feed in in one direction, and the dials are usually quite accurate.
Still, it will be a great advantage of time saving and some accuracy improvement to add a linear scale, at least in the manually-moving direction, so I can mill shoulders and similar features to a very high level of precision and repeatability.
Also the quill will get an electronic readout – but this will be covered later.
Luckily, I had a simple readout around, dating back to 2007, based on an ATmega8515, with some logic, and MAX7219 display drivers.
The case was made from melamine composite boards, these are oil and grease resistant – excellent for workshop use.
Here, the schematic of the input section. The sampling frequency of the counter is about 62.5 kHz, so the TTL signals from the glass scale first pass through a ~160 kHz low pass filter, and are then squared up by Schmitt triggers, 74LS14.
The main processor is running at 16 MHz, and very few extra parts are needed to drive the LED 7-segment displays, using two MAX7219 in chain configuration. The LED segment displays are much preferred for workshop and DRO use, because speed and clarity is everything for this application, and nothing can really replace the good old LED 7-segment displays here.
The power section, note that the regulator will need a heatsink of about 10~15 K/W capacity
– the unit is drawing up to 0.5 Amps at 5 Volts.
The input section…
The wiring, all quickly soldered together with some copper wire.
The code – it uses a gray code approach with continuous sampling of the A/B inputs. This approach is easily coded, and has very deterministic timing, and noise immunity. Any errors found (like, if both lines change state within on sampling cycle) will be indicated by a red LED.
Now, I only need to mount the glass scale (found one that fits in may parts collection…), and replace the “minus” LED (a 3 mm LED) with a minus bar-shaped LED, just for the better looks.
Note that the software has provisions for a matrix key-pad, but for the present application, the “zero” buttons are all that is needed.
This little post may help those that are dealing with rotating or linear encoders, and have been wondering how to build a circuit that actually works, and with a degree of reliability useful for industrial applications. Around machine tools, and similar equipment that rely on such encoders, there is a lot of electric (and audible!) noise, so most hobby circuits that just take some TTL signals and do some quick stuff and calculations won’t work. Let’s try with a real circuit and some good code.
Here is the device, it’s a Heidenhain ST1278, 10x interpolated TTL output micrometer.
According to the datasheet, it has a 20 micron grating, which will lead to a 2 micron signal period, allowing us to get 0.5 micron resolution.
After carefully opening the plug, which has the Heidenhain logo, and secret Heidenhain electronics inside, I can tell you, Heidenhain uses a 75ALS194 line driver, to drive the RS422 output.
We will be using a DS26C32ATM line receiver, to get the differential signal converted back to TTL level.
The differential lines is terminated in 120 Ohms (watch out for their dissipation, if you consider building this in SMD), and has two 220 pF capacitors to absorb and high frequency noise. This thing is running at 100 kHz max.
The output of the DS26C32 is going right to a ATmega328P, sitting on a Arduino nano clone, for convenience. This uses the common CH340G seriell to USB converter to talk to a host computer.
This is the full board. USB power is enough, even for the Heidenhain, and a HX711, which is also used in this device, for other purposes.
How to get the Heidenhain signals decoded into position. Well, we follow a sampling approach here, rather than using any of the rising edges, triggers, etc. – we just sample the two Heidenhain lines at 125 kHz, and compare the sampling result to the last result (of sample N-1), to determine if the Heidenhain moved forward, backwards, or not at all. If both lines change status -we know that something went wrong (e.g., if Heidenhain is moving to fast, or if some noise comes in despite all the effort to keep the noise controlled by the high current differential line).
The 125 kHz sampling is running on a timer-triggered interrupt routine. The duration of the interrupt can be monitored -at least in debug mode- by watching a test pin of the mega328P, by setting the test pin high when the interrupt is called, and clearing it once the service has been completed.
The initial software still used more then 4 microseconds for the sampling, a bit too much, this can be reduced to 2.4 microseconds, even without any special tricks.
Below, you can see the effect of a sampling error (introduced by very quickly pushing the sensor arm inwards), it takes slightly more time to handle the error.
Finally, all that remains is to communicate with the host – this is done at a data rate of 12 Hz, plenty for this application. The data interval is triggered by the HX711 load cell converter, and the the full dataset, including, current encoder reading, error count, load call reading, and time-stamp are transmitted to the host all in one packed, as hex encoded data, and at 19200 baud. All pretty fail-safe and slow, but working just fine, and still a lot of idle time on the line (see transmission pattern on the scope below)!
Below, the avr-gcc code performing all these wonderful tasks.
Thanks to a kind contributor, Mike, about 230 Motorola manuals have found there way into to archive. Included are various detail manuals and service guides of the GP series, and other quite popular Motorola radios.
Happy to receive any of your manual collections related to test equipment, high frequency electronics, or related fields. Will keep them online free of charge for everyone, and all well backed up.
| |– [8.7M] 6864115B18-D GP300 Basic Service Manual.pdf
| |– [421K] AP-73 user manual.pdf
| |– [2.4M] Astro Digital Spectra _ Digital Spectra Plus Basic service manual.pdf
| |– [3.3M] ASTRO Saber Basic Service manual DigitalPort.pdf
| |– [1.6M] Astro service software user guide.pdf
| |– [7.5M] Astro XTL5000 basic service manual.pdf
| |– [1.9M] Astro XTL5000 Detailed User Guide.pdf
| |– [7.9M] ASTROÂ® XTSâ„¢ 2500 user guide.pdf
| |– [897K] BPR_40.pdf
| |– [7.0M] Business Portable Radio service manual.pdf
| |– [363K] Business Portable Radio user guide.pdf
| |– [1.8M] CDM and PRO SERIES detailed service manual.pdf
| |– [2.5M] CDM Series Basic Service Manual.pdf
| |– [8.4M] CDM Series Control Station Service and Installation Manual.pdf
| |– [2.3M] CEP400 basic user guide.pdf
| |– [6.2M] CM140 basic user guide.pdf
| |– [1.3M] CM140 CM160 service manual.pdf
| |– [491K] CM160 user guide.pdf
| |– [3.8M] CM200 CM300 PM400 basic service manual.pdf
| |– [8.7M] cm200 cm300 pm400 detailed service manual.pdf
| |– [351K] CM340 user guide.pdf
| |– [523K] CM360 User Guide.pdf
| |– [2.3M] CM Radios Detailled service manuals.pdf
| |– [1.3M] Commercial Series CM service information.pdf
| |– [160K] CP140_160.pdf
| |– [8.4M] cp150 cp200 detailed service manual.pdf
| |– [5.5M] CP185 Service Manual.pdf
| |– [8.4M] CP200 Detailed service Manual.pdf
| |– [7.0M] Digital XTS 3000TM full featured model user_s guide.pdf
| |– [5.3M] Digital XTS 3000 user guide.pdf
| |– [8.1M] disney2wayadv user manual.pdf
| |– [3.9M] DM 3400 user guide.pdf
| |– [1.1M] DM4400 user guide.pdf
| |– [1.2M] DM4600 user guide.pdf
| |– [7.2M] DP 3400 user guide.pdf
| |– [8.4M] DR 3000 basic service manual.pdf
| |– [8.4M] DR3000 MOTOTRBO Repeater basic manual.pdf
| |– [6.9M] DR3000 MOTOTRBO Repeater basic service manual.pdf
| |– [9.0M] DR3000.pdf
| |– [ 79K] Emergency Foot Switch instruction manual.pdf
| |– [5.2M] EP450 basic service manual.pdf
| |– [1.5M] EP450 detailled service manual.pdf
| |– [ 63K] Flashing Adapter HLN9742 Service Manual.pdf
| |– [345K] FLASHport user guide.pdf
| |– [4.0K] GM1200E detailled service manual
| | |– [1.6M] dsm_a3s.pdf
| | |– [249K] dsm_a4s.pdf
| | `– [924K] GM1200E_SM _EN.pdf
| |– [924K] GM1200E service manual.pdf
| |– [326K] GM1200_UG_EN.pdf
| |– [889K] GM1280 user manual.pdf
| |– [1.4M] GM300 basic service manual.pdf
| |– [808K] GM300 service manual (3 parts).pdf
| |– [ 14M] GM300 service manual.pdf
| |– [217K] GM340 user guide.pdf
| |– [4.0K] GM350 installation manual
| | |– [440K] 350IN_EN.pdf
| | |– [ 25K] 350RS_EN.pdf
| | |– [ 74K] 350ug_en.pdf
| | `– [119K] 950rmkit.pdf
| |– [561K] GM360 user guide.pdf
| |– [692K] GM380 user guide.pdf
| |– [722K] GM-660_Manual.pdf
| |– [871K] GM series Radio Installation manual _ service manual.pdf
| |– [119K] GM Series service information.pdf
| |– [3.3M] GP1280 basic service manual.pdf
| |– [1.9M] GP1280 user guide.pdf
| |– [4.0M] GP300 Basic service manual.pdf
| |– [231K] GP300 Service manual (schematics).pdf
| |– [1.9M] GP320 user guide.pdf
| |– [8.4M] GP328 GP338 Detailed service manual.pdf
| |– [8.1M] GP328 Plus detailed service manual.pdf
| |– [453K] GP328plus GP338plus GP338XLS Basic service manual.pdf
| |– [8.1M] GP328plus GP338plus GP338XLS detailed service manual.pdf
| |– [4.1M] GP330 user guide.pdf
| |– [1.9M] GP340 Ex Portable Radio basic user guide.pdf
| |– [2.2M] GP340 user guide.pdf
| |– [257K] GP344 user guide.pdf
| |– [3.4M] GP350 service manual.pdf
| |– [4.0K] GP350 User Guide
| | |– [374K] gp350_part1.pdf
| | |– [1.5M] gp350_part2.pdf
| | `– [703K] gp350_part3.pdf
| |– [1.8M] GP360 user guide.pdf
| |– [2.8M] GP380 Ex Portable Radio basic user guide.pdf
| |– [1.9M] GP-380_Manual.pdf
| |– [1.2M] GP388 user guide.pdf
| |– [4.4M] GP580 Ex Portable Radio basic user guide.pdf
| |– [4.0M] GP600 series Basic Service manual.pdf
| |– [2.2M] GP640 GP680 Basic Service manual.pdf
| |– [1.8M] GP640 GP680 Basic User Service manual.pdf
| |– [2.2M] GP-680_Manual.pdf
| |– [1.3M] GP68 User Guide.pdf
| |– [4.0K] GP Series detailed service manual
| | |– [384K] B32E_Sect1_Service Maint.pdf
| | |– [518K] B32E_Sect2_Keypad_A3.pdf
| | |– [ 89K] B32E_Sect2_Keypad_A4.pdf
| | |– [576K] B32E_Sect3_Controller_A3.pdf
| | |– [210K] B32E_Sect3_Controller_A4.pdf
| | |– [2.6M] B32E_Sect4_VHF_A3.pdf
| | |– [255K] Chap 1 Introduction_A4_v0.pdf
| | |– [234K] Chap 2 Theory of Operation_A4_v0.pdf
| | |– [718K] Chap 3 Maintenance_A4_v0.pdf
| | |– [551K] Chap 4a Controller and Keyboard Info_A3_v0.pdf
| | |– [240K] Chap 4a Controller and Keyboard Info_A4_v0.pdf
| | |– [525K] Chap 4b VHF Info_A3_v0.pdf
| | |– [510K] Chap 4c UHF1 Info_A3_v0.pdf
| | `– [511K] Chap 4d UHF2 Info_A3_v0.pdf
| |– [9.3M] GR300 GR500 service manual.pdf
| |– [2.3M] GTX LCS 2000 service manual.pdf
| |– [968K] HF-SSB Automatic Antenna Tuner owner_s manual.pdf
| |– [573K] HKLN4197A_PRO2150_Eng.pdf
| |– [9.3M] HT1000 JT1000 MT2000 MTS2000 MTX series Service manual.pdf
| |– [477K] HT1000 MT2000 MTS2000 MTX series Service manual.pdf
| |– [4.3M] HT1250 user guide.pdf
| |– [4.9M] HT750 HT1250 MTX850 MTX1250 MTX8250 MTX9250 basic service manual.pdf
| |– [1.9M] HT750 HT1250 MTX850 MTX1250 MTX8250 MTX9250 supplement basic service manual.pdf
| |– [ 12M] HT800 VHF service manual.pdf
| |– [3.0M] HT90 service manual.pdf
| |– [2.2M] HT Series detailed service Manual.pdf
| |– [2.2M] LCS2000 service manual.pdf
| |– [1.4M] LTS 2000 user_s guide.pdf
| |– [6.9M] Mag One basic service manual.pdf
| |– [1.7M] MagOne Basic Service manual.pdf
| |– [433K] Mag One BPR40 Brochure.pdf
| |– [4.8M] MagOne detailled service manual.pdf
| |– [2.1M] MCS 2000 Mobile Radio.pdf
| |– [295K] MCS 2000 Model I User Guide.pdf
| |– [306K] MCS 2000 Models II _ III user manual.pdf
| |– [2.1M] MCS2000 service manual vol-1.pdf
| |– [1.1M] MCS2000 service manual vol-2.pdf
| |– [1.3M] MICOM-2E ALE owner_s guide.pdf
| |– [ 36M] motorola gm 900_sm.pdf
| |– [533K] MOTOROLA KIT HSN4035 Service Instruction.pdf
| |– [647K] motorola Models T4800 T4900 Instruction.pdf
| |– [1.2M] motorola Models T5600 T5620 T5700 T5710 T5720 instruction.pdf
| |– [1.4M] motorola Models T5800 and T5820 instruction.pdf
| |– [1.0M] motorola Models T5900 T5920 and T5950 instruction.pdf
| |– [ 38M] motorola mototrbo dp3400 3401 3600 3601 sm.pdf
| |– [101K] Motorola NMN6250 NMN6251 – service manual.pdf
| |– [7.0M] motorola_novacommunications_business_portable_radio_cp125.pdf
| |– [7.0M] motorola_nova_cp125_sm.pdf
| |– [372K] Motorola P040 P080 Controller – schematics.pdf
| |– [533K] Motorola P040 P080 UHF – schematics.pdf
| |– [772K] Motorola P040 P080 VHF – schematics.pdf
| |– [1.5M] Motorola P200 – operating instructions.pdf
| |– [1.5M] Motorola PRO3100 UHF – schematics.pdf
| |– [2.3M] Motorola PRO3100 VHF – schematics.pdf
| |– [2.3M] Motorola PRO5150 – schematics.pdf
| |– [196K] Motorola Systems Saber – UHF specifications, service manual.pdf
| |– [196K] Motorola Systems Saber – VHF specifications, service manual.pdf
| |– [387K] Motorola T4502 – instruction manual.pdf
| |– [3.5M] Motorola T4512 – instruction manual.pdf
| |– [4.2M] Motorola T5022 – User.pdf
| |– [3.2M] motorola T6200 T6210 and T6220 instruction.pdf
| |– [5.2M] Motorola XTL1500 users guide.pdf
| |– [2.2M] Motorola XTL2500 users guide.pdf
| |– [9.7M] Motorola XTS4000 basic service manual.pdf
| |– [6.0M] Motorola XTS4000 detailed_service_manual.pdf
| |– [3.0M] Motorola XTS4000 user service manual.pdf
| |– [3.6M] Motorola XTS4250 – advanced model user guide.pdf
| |– [2.7M] Motorola XTS4250 user guide.pdf
| |– [2.0M] Motorola XTS5000 parts list.pdf
| |– [ 34K] Motorola XTS5000 service aid sheet.pdf
| |– [5.2M] Motorola XTS5000 user guide.pdf
| |– [5.7M] MOTOTRBO DR3000 Repeater basic service manual.pdf
| |– [516K] M-Series Owner_s manual.pdf
| |– [1.6M] MSF 5000 maintenance and alignment manual.pdf
| |– [ 44M] MSR2000 Control _ audio operation _ service manual.pdf
| |– [ 37M] MSR2000 operation and service manual.pdf
| |– [8.3M] MT1500 basic service manual.pdf
| |– [1.9M] MTH500 Basic Service Manual.pdf
| |– [4.0M] MTH500 Tetra Detailed Service Manual.pdf
| |– [1.2M] MTH650 Tetra Basic User Guide.pdf
| |– [3.3M] MTH800 TETRA basic service manual.pdf
| |– [4.3M] MTH800 TETRA basic user guid.pdf
| |– [5.8M] MTP700 Detailed Service Manual.pdf
| |– [2.1M] MTP810 Ex TETRA basic service manual.pdf
| |– [2.1M] MTP850 EX Basic Service Manual.pdf
| |– [8.4M] MTP850 TETRA basic service manual.pdf
| |– [2.2M] MTX Series detailed service Manual.pdf
| |– [3.8M] MX300-S series service manual.pdf
| |– [4.0K] p040-080_all_man
| | |– [1.9M] 10B67_UG.pdf
| | |– [2.3M] 10B68_UG.pdf
| | |– [163K] 13B29_CPS.pdf
| | |– [926K] 14B36_SG.pdf
| | |– [4.5M] 15B49_BSM.pdf
| | `– [ 40K] ENLN4122A.pdf
| |– [2.7M] PM400 Basic Service Manual.pdf
| |– [ 11M] PM400 Detailed Service Manual.pdf
| |– [3.7M] PR400 Basic Service Manual.pdf
| |– [9.5M] PR400 Detailed Service Manual.pdf
| |– [1.8M] PRO Series detailed service Manual.pdf
| |– [2.3M] R-1011B Instruction manual.pdf
| |– [392K] R-1013A operation _ service manual.pdf
| |– [6.9M] R-1100A Operation manual.pdf
| |– [1.4M] R-1150 R-1151 operation manual.pdf
| |– [2.5M] R-2008C Operations manual.pdf
| |– [ 48M] R-2200A service manual.pdf
| |– [3.5M] R-2200 R-2400 operation manual.pdf
| |– [3.6M] R-2600 SERIES Operator manual.pdf
| |– [1.0M] Radius CM200 installation guide.pdf
| |– [769K] Radius M100 M200 Owner_s manual.pdf
| |– [3.5M] RLN-4008B service manual.pdf
| |– [2.7M] S1051C S1053C operation _ service manual.pdf
| |– [4.4M] S1067A operation and service Manual.pdf
| |– [ 12M] S1318A S1319A S1320A S1321A S1329A operation _ service manual.pdf
| |– [267K] SABER Portable Radios user_s guide.pdf
| |– [191K] SABER Theory _ Maintenance manual.pdf
| |– [1.3M] SM_GP68.pdf
| |– [3.9M] Spectra Conventional Radio System Operating Instructions.pdf
| |– [458K] Spectra Privacy Plus Operating Instructions.pdf
| |– [573K] Spirit GT Operator_s manual.pdf
| |– [3.6M] SSE 5000 service manual.pdf
| |– [8.4M] Syntor X Maintenance and troubleshooting manual.pdf
| |– [3.3M] TETRA MTH800 basic service manual.pdf
| |– [1.7M] TETRA MTP850 basic service manual.pdf
| |– [ 10M] XPR7000 basic service manual.pdf
| |– [ 11M] XPR 7000 Seris basic service manual.pdf
| |– [4.0K] XTL5000
| | |– [2.0M] 96C67-C_AX_UG_XTL5000_W3.pdf
| | |– [1.9M] 96C68-D_AX_UG_XTL5000_W4579.pdf
| | |– [3.2M] 98C38-O_v4.pdf
| | `– [622K] 9964416H03_O_XTL5000_AT_IM_Dual-Radio_CH.pdf
| |– [6.2M] XTS1500 XTS2500 basic service manual.pdf
| |– [698K] XTS3000 parts list.pdf
| |– [698K] XTS3000 XTS3500 parts list.pdf
| `– [625K] ZR310 service manual.pdf
Winter time, is workshop time, spending several hours in the workshop every week, either in the ground floor workshop, or basement rooms – and on several instances, missed the postman! Especially on Saturday, when nobody else is at home, an I am waiting for some spare parts!
The simple reason, the door bell only rings in the office/apartment on the 3rd floor, but I can’t hear it in any of the workshops. This needs to be solved – but how? Running a wire through several floors is no option.
Browsing through online offers, I found some low-cost wireless doorbells (120 meters range!! probably, Chinese meters but fair enough) and came up with this scheme – the 3rd floor apartment door bell, which is integrated into a Siedle-brand HT411 door phone will trigger the transmitter of the wireless door bell, which in turn will give its sound in the workshop are.
This is the xbay offer – one transmitter, and two receivers.
That’s the HT411 with the transmitter mounted.
The door bell uses a transformer-less powder supply… let’s hope it will last.
Finally, the simple schematic using the “ring” signal of the HT411, which is 12 VAC to activate the door bell transmitter (with the button shorted, it will activate the received whenever power is applied!).
All is working loud and clear now, you push the main door button, then the HT411 will ring in the apartment 3rd floor, this in turn will active the wireless transmitter, and both receivers will sound in the 1st and basement workshop. Easy enough!
For several years, I have been using hacksaws and similar tools, and other less suitable and dangerous tools to cut-off metal stock for milling and turning. Or, I used some friends’ equipment, which is troublesome and time-consuming – to travel to far-away places just to cut some metal.
With the space I have in the basement, there is no room to fit a large industrial band saw, and I wanted to get a machine that can also cut at an angle, for some welding and fabrication work. The machine selected, a Holzmann BS 128HDR is one of the common Chinese designs, but these are not all made equal, and the Holzmann looks like a good brand. Cutting capability is 125 mm diameter round, 100×150 mm square, which should be good for 99% of the work.
All came in two boxes, on a wooden pallet.
Some tests with 42CrMo4, and 26CrMo4 rod. It is cutting perfectly fine. Also checked with some square tubing, which can be challenging for some cheap band saws because of the thin-walled sections, but the 128HDR has a hydraulic break/mechanism, which provides smooth cutting action even for these more difficult materials.
For lubrication, you can use any type of ordinary oil, HLP 68 hydraulic oil works well and is cheap, with no smell.